Cryptocurrency now is use to avoid sanctions and different bans for different donations.
So the use of cryptocurrency only will increase in the future.
DeFi exchanges usually do not connected with fiat. They only work with cryptocurrencies.
Do you work with fiat?
How do you this is it important for exchange to work with fiat?
Usually CEX use fiat. But it is not safety to hold money on CEX. CEX can be hacked and CEX can block the account of users.
Now many CEXs blocks the accounts of traders from Russia.