There is still the question of how to convert your crypto to actual spendable dollars again. Sure, uniswap will let you get another token but you still need an exchange to get dollars. This gets particularly important when, say, the giant scam that is Tether finally crashes and burns,

Yes, a regulated centralized exchange is valuable for on and off ramp. All they would need to do is process user transactions, take a small fee, and not gamble with user funds. Regulators could do audits and keep consumers protected.

But regulators have failed to provide clear framework for exchanges in the US[1], so most CEXes are running off shore.

[1] https://www.cnbc.com/2022/11/11/op-ed-crypto-markets-need-re...