Eg if ETH starts being used for most transactions, and BTC started crashing in value would anyone feel a need to keep it?
Edit: The above is a rhetorical question.
So, if you invest in Euros in the US, and the dollar falls relative to the Euro, you owe money to the IRS — and vice verse for the Euro in Euro-countries. It’s difficult for competing currencies to gain traction when you owe money if the legal tender drops in value (relative to the competing currency).
A. A dollar bill represents an accounting entry in a bank account. Banks are the third party that facilitate trust and the rules by which 2 actors trade. B. Dollar bills are legal tender for the payment of taxes. They are enforced by government, which is the sole legal arbiter of coercive action. Taxation requires every citizen to hold a reserve of state currency. C. Due to the specialized printing process dollar bills are, at least theoretically, hard to counterfeit. D. Ubiquity as trading mechanism, barter requires double coincidence of wants (rare) or interpersonal credit (lack of third party oversight to guarantee fair play). When holding assets, these can deprecate (or appreciate) in value, and would need to be converted in cash holdings to avoid the impracticalities of barter exchange. E. They are an convenient way of turning digital entries into tangible user objects, since they hardly take any space.
I'm sure you could keep the list going. Notice how cryptocurrencies satisfy a lot of those conditions. Also notice how bitcoin in particular fails at a number of them.
I don't understand your point. I can understand we will have multiple crypto currencies, but if there are unlimited number of currencies, why would any of them have any value?
That's not the whole story though, some of these other cryptos also serve as a testbed for new concepts & improvements, differ in particular ways to better suit a specific purpose, target different markets, have different core values or are alltogether alternate technical implementations.
Each one of those nuances adds some deegree of value. As with any stock or other economic asset, their price today is not necessarily reflecting the value it has for practical use today, but rather the possibility that it will become necessary or more dominant in the future.
2) Economics. Bitcoin is deflationary. There will only ever be 21m Bitcoins. Ethereum does not have a hard cap on the max number of Ethers. Each coin has its own economics. Smart investors will understand the economics behind each coin they buy into. Otherwise you end up buying Ripple at 40 cents each thinking its a bargain...
So much so, that when trading other crypto currencies you're usually trading via BTC.
BTC holders, at least.