But what would make me to use cryptocurrency with a negative interest rate? Of course all kind of cryptocurrencies can exist, it wouldn't be a surprise if there were already some kind of negative interest-rate model in some of the 100's of altcoins. But the user decides what kind of cryptocurrency he uses.
I decide what kind of global currency I use, and how it is stored. But in the same way trading in and out of bitcoin costs money, so does FX.
Until large numbers of retailers accept bitcoin directly it's just a different currency with a less stable exchange rate, lower liquidity and a higher potential for low tech users to get their money nicked.
You can't use a cryptocurrency on your own. The network effect is strong and it's unlikely that more than a few useful cryptocurrencies will emerge.
There is a reason why negative interest rates exist now. It would be foolish to assume that those reasons go away and won't be implemented into cryptocurrencies in the future if they are used widely.
Based on your comments, I don't think you understand cryptocurrencies very well. Who would get the money from negative interest rates? Miners?
If miners are so powerful that they can change the protocol rules, why they wouldn't just raise the block reward? ( increase inflation/monetary expansion)
I do understand how cryptocurrencies work. Negative interest rates don't have the same effect as inflation and could be implemented in code. Just because miners have the same nominal changes in their wallets doesn't mean that the effect on anyone else is the same.
I just don't think our current problems with currency go away just because we use cryptocurrency. There is no reason to. Central banks don't enact policies because it's fun but because they think it will have a certain effect. People will find a way to do so in the future. Whether it's called "Inflation" or "negative interes rates" or whatever is not relevant. The only thing that matters is what happens to people's money.
Oh, and it would be much easier if you would actually reply to my comments (instead of yours). If neccassary wait a few minutes to do so.
I guess the difference is that it's users are not at the mercy of bankers (made of flesh, tradition and law) but instead predicable computer programs (made of logic & code).
Your dichotomy is imaginary. The computer programs are made by programmers (made of flesh, tradition and law), and bankers usually don't directly make the calls, instead relying on their programs (made of logic and code).
That is only partially true. Only very non-controversial changes manage to get through. You can see from the current blocksize debate that it is quite difficult to change the bitcoin protocol.
Also majority of hash power doesn't decide everything. If miners decide to create cartel where they change the protocol rules (via hard fork), they still need a place where they need to sell those mined coins. So exchanges/services/merchants should be in the same boat.
Also there will be always a lot of competing cryptocurrencies, where users can switch to when needed.
How is that different from regular currency? It is quite hard to implement laws that effectively enable negative interest rates. You can see that in, well, this discussion.
What really happens is that power is shifted away from regular people (who can at least assert some influence on those making the changes) to those holding capital.
The user is still at the mercy of someone: In current implementations at those who have a majority of computing power in the network. Code changes in Bitcoin have happened in the past and will happen in the future.