I want federation to work. But this is a fair critique of the tradeoff and competition between centralized and federated services - and the dynamics of network switching instead of host switching.
Everyone loves to rag on signal here it seems. They would rather something be correct in ideals than help the largest amount of people. It’s a strange and holier than thou stance to take in my opinion.
So I don't think "it's impossible to make a non-shitty federated client" is really a valid argument. That's not to dispute real problems with wide-open federation or XMPP, because they absolutely exist, just that "the clients are hard to use" seems more an artifact of the resources of the people making them than anything to do with technical merit.
Perhaps not, but it's definitely a strawman.
I imagine federated chat means more opportunities for your users to avoid seeing ads too... Just use someone else's server!