As for me Bitcoins high volatility is the main problem for todays crypto and its image in the World, that's what prevents fiat replacing for the current moment.
Bitcoin's volatility is very high compared to fiat currencies, so many countries prohibit bitcoin with the reason to protect the country's citizens from huge losses. On the other hand, high volatility is favored by speculators because it has a large capital so that the money invested is large, the profits are also very large.