Edit: @potench preev.com is an inaccurate indicator of the BTC/RUB rate because it is basing its calculation "based on the USD Bitcoin price" per its footnote, so of course it will never show a big deviation from the BTC/USD rate. For the true rate you need to look at the real-time bid/ask spread on a BTC/RUB exchange such as btc-e.com which is why I linked to https://bitcoinwisdom.com/markets/btce/btcrur or you can also look at https://btc-e.com/exchange/btc_rur: bid/ask is 20855/21099 RUB as of 22:09 UTC, so the arbitrage opportunity is approximately 2000 RUB.
If people think such a scenario can't easily happen again, then they're wrong about that. A small number of major bitcoin holders mostly determine the price.
Sorry but fiat currencies possess no advantages other than incumbent localised network effects. The world needs a true global currency and Bitcoin is it.
Alternatively, wait a few hundred years until you need several hundred terabytes to store the blockchain, which is required for transactions. That's going to be a problem.
Or you could switch to Bitcoin before realizing that currencies which deflate in value are a terrible idea.
(For the record, I support cryptocurrency. I just think Bitcoin has too many issues to be viable long-term. Nice proof of concept, but it needs to be refined).
That wont be developed overnight, by the time it is a possibility people will be working on solutions. a quantum computer would impact a lot more than bitcoin, all cryptography would become useless.
>Alternatively, wait a few hundred years until you need several hundred terabytes to store the blockchain, which is required for transactions. That's going to be a problem.
With the cost of storage rapidly reducing then that probably wont be an issue in a few hundred years.
>Or you could switch to Bitcoin before realizing that currencies which deflate in value are a terrible idea.
Currencies that inflate have had their share of problems and we certainly have not found a way to solve those problems or the issue of inflation/hyper-inflation. Any problems with delfationary currencies (which you do not detail) are merely hypothetical as no real deflationary currency has existed before.
That's really bad for an economy.
My ideal cryptocurrency would constantly "leak" money, trying to maintain a 0.1% or so inflation rate a year, to prevent this problem.