Those criticisms seem reasonable. Regarding package signing, are you referring to github.com/NixOS/nix/issues/613#issuecomment-1343…? Additionally, that default for pip seems veritably insane. I understand using system packages, but modifying packages outside the virtual environment is definitely weird.
I used it yesterday, via Pidgin. I’m rokejulianlockhart@xmpp.jp. Why else would I have referenced it? Don’t tell me what I’ve done. That’s not a way to have productive conversations.
Regardless, I can’t provide any more technical insight than that - I know solely that the clients provide so much more functionality that irrespective of the protocol, it’s better in practice. Fedora, openSUSE, the Bundeswehr, NATO, and Beeper - all chose Matrix over XMPP, not least partially because of Element (which they also all chose).
I don’t believe that its existence causes more fragmentation than it remediates. news.ycombinator.com/item?id=36939482 explains why I consider Matrix fundamentally superior most (if not all) uses, although in practice it’s because the clients (Element and FluffyChat primarily) are cross-platform and support a generally uniform set of features, in comparison to the aged (but glorious) Pidgin, and its counterparts.
Yeah, my experience with Element and a Matrix.org account is that it’s sluggish. However, it’s been better at Beeper, so I’m uncertain whether it’s intrinsic to Matrix or merely Matrix.org and/or Element’s servers.