In general, while it makes for convenience for end-users, I'm just not interested in hitching my buggy to another "single point" social media platform.
I already have a Discord account, I don't really need to sign up for a Discord clone based on a "Trust me Bro" sort of guarantee that they won't enshittify it in the future. Because nothing really stops the Revolt developers (and I'm not trying to imply any evil intentions, or even plans on their part) from deciding to accept VC money, or just sell the whole thing outright to $corporation_with_a_dumptruck_full_of_cash, and there's not a thing that a User can do about it.
It's entirely possible that with Matrix, that an individual matrix server administrator (lets call it matrix.foo.bar) could get up to shenanigans, but as it's a federated chat protocol by design, I'm free to take my custom elsewhere (matrix.bar.foo), and basically have the same access to all the things I did before. There is no single point of control, or failure for somebody to break, or sell.