You already know the answer:  volatility. People are unwilling to hold bitcoin for transaction purposes because the value fluctuates so much.   I guess it's a glass half full/empty thing, though: in less than 20 years, bitcoin has established itself as a spontaneously emerging alternative to fiat money. And for countries where inflation or confiscation risk is high, it is ALREADY an important form of currency for trade. El Salvador tried bitcoin as "legal tender" but it has not become dominant, even there.

mungowitz

Bitcoin is the most tolerant form of money. No one decides the rules or has to use it. If you don't like something about it, you can launch your own coin with different rules (although that might be a mess if you may have trouble convincing people to accept it). What do you think stands in the way of increased use of bitcoin in trade?