What's your question about crypto?
And behind "normal currency" I hide a lot of things that I don't know about. Does it has to be stable? Does it have to follow a real currency like the USD?
Transaction cost: about $0.75 on Ethereum or $0.01 on Polygon at the moment - no size limits. Zelle is free up to ~$1,000 per day.
Settlement: 12 Seconds on Ethereum or 2 Seconds on Polygon, "instant" on Zelle. However many transfers on Zelle use ACH under the hood, so it may take 3-5 days to settle with your bank. If the recipient isn't enrolled in Zelle it may take 14 days for them to register to receive funds.
I'll note that I regularly move USD around as part of my job and have always found USDC to be a superior experience than bank transfers - especially because I can use smart contracts and custody tooling to set custom transaction policies on required approvers, whitelisted recipients, etc.
There's one giant benefit of using cryptocurrency and a few smaller niches. It is a currency of last resort to guard against hyperinflation or currency controls or for drugs. You should really only be using it if you can't turn your money into dollars but can earn cryptocurrency another way.
Check out an example like https://mission.org/hidden-in-plain-sight/bitcoin-a-lifeline... . In this case its easier to earn crypto as payment for doing work online than it is to be paid in USD.
The smaller niches include things like flash loans
Flash loans are actually new thing in the world but still pretty dangerous. You can get a massive massive loan (Think $1 billion) without putting anything down as long as you pay it back in the same transaction you get it. Ethereum can guarantee the loan and repayment succeeds so the borrower really can loan $1 billion. Of course this only works as long as whatever tool the loan contract is using to check that the borrower can repay $1 billion works. If not then the money is going to be stolen...
As for goal, there isn't one. Its whatever folks want it to be and a large number think ponzis are the goal...
As for normal currency, it does not need to be stable. See Venezuela as recent example. It typically can't follow a real currency like USD exactly. In fact trying to keep an exchange rate between a strong currency and something else the same almost always ends horrifically like https://en.wikipedia.org/wiki/Black_Wednesday
They mostly aren't suited to this. A desirable property in a normal currency is relative stability (generally with small, managed levels of inflation to encourage useful investment). But in order to bootstrap a cryptocurrency you need to get people interested in using it to establish a value, so you set up the currency in a way that disproportionately rewards early adopters and encourages speculation, to pull people in. This in turn makes it a lot less stable and you see where this is going
> What would be the benefit of using a cryptocurrency?
For those who are true-believers, the idea is that you have currency which is free from government manipulation, free from authority, is unstoppable, uncensorable, irreversible, may be anonymous etc etc.
For those of us who are not, most of those are actually negatives. Plus an honest evaluation of the largest cryptocurrencies often shows they don't fulfil these pipedreams anyway. Bitcoin, for instance, can be censored if wallet addresses are known and the government manages to get 'miners' onboard with a blacklist. Exchanges can refuse to accept deposited funds unless they come from known, KYC/AML compliant organisations. And given that mining BTC is a huge, expensive, energy and equipment intensive operation, there are not actually all that many firms, so collusion is a definite possibility, and with about half the hash power they could collude to block transactions.
> Is the goal to be used at a large scale globally or would it at best remain niche?
There are as many aims as there are users. Some want complete freedom from government monetary interference, implying large scale use. Some want to revolutionise the finance sector and disenfranchise the established banks. Some are basically addicted to gambling. Some want to get rich, and see it as an easy way, or the only way. Some just want to facilitate 'dark' transactions (contraband of various forms).
> Does it has to be stable?
No, but there are so-called stablecoins which attempt to peg their value to normal currencies, specifically the US dollar. Some attempt to do this algorithmically - see Terra/Luna/UST and the chaos from that collapse earlier in the year. Most algortihmic stable coins are vulnerable to some sort of bank-run scenario.
Others attempt to do it by having their stablecoins backed 1:1 with the normal currency they are pegged to, the largest of these is "Tether" also known as USDT. They used to claim there was a dollar in a bank-account for every token issued, but they refused audit for years and eventually dropped the claim. They have various redemption barriers ($100k minimum payout, for example) to stop any sort of run from happening, and there are strong feelings in crypto communities and sceptic communities that they are playing fast and loose, and have perhaps backed a lot of their tokens retrospectively (create token, use it to buy an asset, now that token is backed) or purely manipulatively (giving out billions to friendly exchanges to use to prop up BTC prices without getting any more backing than an IOU).
> Does it have to follow a real currency like the USD?
That seems to be the gold standard here! Though stablecoins against other currencies probably exist, and I believe I heard about gold and silver backed stablecoins at some point. The problem with all of the backed ones is "Hey, I have this massive bank account, just sitting there backing my coin, surely nobody would notice if <shenanigans>"
Just reading the thread here though reminded me of one: is crypto traceable by the feds or not? I've seen people very confidently declare both.
Other protocols, such as zcash, specifically obfuscate the inputs and outputs using cryptography, in ways that I'm not specifically sure how to explain, but are supposed to work.
In some ways to me this is unsurprising in a way different from the ponzi nature of crypto. I can't explain Ed25519 either, and I'd also get bogged down reading a paper explaining it. I can get my head around the basics of btc and pre-proof-of-stake ethereum though, this[1] 3Blue1Brown video went a long way.
Definitely not going to disagree that lots of tokens are ponzis, and lots of the tech and promises are imaginary vaporware. But there are some real pieces of tech in the mix too.
[0] https://blockstream.info/block/00000000000000000003590ca79f7...
In general it is considerably easier to unmask people using crypto than other methods because perfect security is hard (criminals are dumb).
Tornado Cash previously broke that trail using asset pools, but that has been sanctioned now.