Well if you have someone that thinks their money in RUB might go way down they might want to exit into a cryptocurrency which isn't controlled by fiat.
Demand goes up, supply stays the same, price goes up.
Yes, but with capital markets, there are real world assets anchoring the stock market.
With crypto, the whole cycle is pure pricing. Say a bank converts crypto to money, the bank has no other way to use the crypto, other than selling it back on the exchange, presumably to other retail "investors" or other banks.
With no asset actually anchoring it, a crypto is an extremely weak pricing product that moves with sentiments, emotions and feelings.
Demand goes up, supply stays the same, price goes up.