That being said, as for me looking for alternatives, I mostly focused on the "centralized" part.
I looked into Delta Chat (npub17gp…nrxn) and, on one hand, it looks to be a great Thunderbird replacement after the current Mozilla ToS fiasco, but, as for a Signal replacement, so so much. Privacy-unaware people would skip it, from the rest, those skimming over it the webpage would be afraid of it using e-mail, and those reading the FAQ would notice it doesn't support Signal's sealed senders (or a similar feature) yet, making it look inferior.
As for me, webxdc apps makes me as adverse to it like when Signal added payments: it sounds like feature creep, and IMHO it means developers are spending time with things that should not be the focus. As the Unix philosophy says: "do one thing and do it well". 😕