> Dollars have one major advantages over bitcoins (in the US): They are legal tender for paying all debts, private and public.
This is true, but the practice is such because the government has previously granted a monopoly on the issuance of money to certain private entities which have little accountability to anyone. Previously, it was not possible to compete with this monopoly, because the state enforced it through the threat or use of violence.
The money issuers now have competition, and the government has no way of "shutting down" the competition due to the way it was designed. Merchants now have alternative options in terms of what currency they're willing to accept and how they can save money, rather than simply spending.
If it happens that the new competition is more desirable to possess than the previous money (due to lack of inflation, meaning it is more likely to retain its purchasing power in the long term), then people will save in bitcoin, and spend in dollars.
The result is that a large amount of wealth will essentially "disappear" from circulation which the state thugs can levy taxes on via use of violence. Economies will take a hit as a result, but the people saving in bitcoin won't be impacted as heavily as those who don't. In fact, it could have the effect where each hit taken by a national economy drives more people to bitcoin, pushing up the demand and value, making those who were smart enough to accumulate it earlier even more wealthy than before the economy took the hit.
As long as there are liquid enough markets (whether those are AML/KYC compliant, or black-market) for people to trade some of their bitcoin back into USD for the purpose of paying taxes, then the dollar is not going to retain its advantage.
> Bitcoin also has a cost associated with it that the dollar does not - a transaction processing cost (yes, there are costs for the handling of money, but it's both significantly less than bitcoin transaction costs, and is relatively constant).
Transaction fees in bitcoin are not consistently high. Some fees were high last year due to the sudden increase in speculation, poor fee estimation in software, and services which were not making efficient use of block-space, at their own cost, or the cost of their clients. Much of this has improved, although we have a long way to go.
The main developments are in the more scalable technologies pinned to bitcoin, which aren't competing entirely for a share of the limited block space. Fees on the lightning network, for example, have a base rate in satoshis (per transaction), and a proportional fee of 1 millionth the value transacted. The fees total fractions of cents. Bitcoin transaction fees are only paid in the creation and destruction of payment channels, which may be very infrequent.
> WRT deflation, the biggest problem (that I'm aware of) is that it disincentivizes spending, something generally considered to be a bad thing for the economy. Sure, people may buy the necessities with a currency that is deflationary, but they're disincentivized by the currency itself to do anything more than that.
The reason that reduced spending is seen as a "problem," is because governments can't cover the interest on their debts unless people are actively spending and paying taxes on those transactions. Governments are not really paying their debts off - they're paying off the interest, and kicking the can down the road even further. The debt will never actually be paid. It is impossible to pay off. At some point, who knows when, your government is going to default. This is inevitable.
> In other words, why would anyone (not just the rich) spend more than the bare minimum when not spending means their net value increases?
People spend because they want something, and they're willing to let go of something else which they value in exchange. For some that might be the bare minimum. For others, they might want to continue wealth-signalling with expensive cars and watches.
Think about that one. The value of that car depreciates by about 20% immediately upon purchase, and then by a further X% every year. It has a lifetime of around 10-15 years before it is basically worth the value of its scrap metal. Yet people are still buying cars frequently. Could it be that people still spend money on products and services which provide them value now, and not just save everything like the deflationary scaremongers suggest?
> Any form of investment that can't accrete value faster than the currency itself becomes a wasteful product. Stocks, bonds, houses, cars, bicycles, startups, family businesses, education - all have the potential of losing all their value when compared to hording currency.
Some of the examples you pick, like cars, bicycles, houses (sometimes), actually depreciate in value over time, which throws away the argument that people won't spend money if they don't see a monetary ROI.
Consider renting a home as another prime example. People will continue to put money into an "investment" which will eventually net them zero return when they move home or get evicted. Yet people still rent.
Many "investments" are simply full of rent-seekers who do not provide any real value to society. If people stop throwing money at these, it won't be missed.
Education is an example of something we can't even measure the ROI on. We just know from observation that the better educated a society is, the higher its productive capacity appears to be a few generations down the line. We also know that some academies do a better job than others, and that some people are willing to pay more to have their children educated at those academies, with no guarantee that they will see a ROI. (The child could turn out rebellious, or just not smart anyway). People still invest in education despite there being no obvious profit motive - their child's future is more important than the value of the money.
The real difference in investment when it comes to deflation is that people simply make better decisions. The incentive is skewed more towards saving than spending, but this is not absolute. People will spend, but think twice about buying that useless gadget that they didn't really need, but they bought on impulse because they had $1000 burning a hole in their pocket.
The argument against deflation is essentially the same as saying "people won't save money if there is inflation," because money is depreciating over time. The incentive is towards spending, but people still save money. The only time they don't save is during hyperinflation, when the value of the money depreciates more rapidly than they earn and spend it. The reverse is true for a deflationary economy. As long as deflation is low, people will still spend, but with more preference to save. It is only if hyperdeflation occurs that people will "hodl" and only spend the bare minimum to survive. Hyperdeflation will occur as bitcoin gains adoption, but it is not the eventual state. Once peak adoption has occurred, the rate of deflation will begin to decrease, with the eventual state that it will be relatively stable. In the even longer term, bitcoin could become inflationary by accident, if the human population as a whole begins to decrease rather than increase - because demand will be reduced.