The ability to defederate arguable makes it more free & open even if it isn’t what I would prescribe.
I recall having some fun with League of Legends when you could just join chat & chat rooms thru a regular XMPP client. This was convenient at work on Linux to not need a working client to catch important messages from teammates. But everyone wants a walled garden now.
I use the note to self capability of my XMPP server to send a message to myself for these sort of one-offs. I would never want my data in the hands of some proprietary service if I have the option—sharing data just to yourself on these services also means it is Big Tech’s data now too. All of the XMPP clients are super lightweight.
Bigger cases, I will use scp, rsync, or magic wormhole. Or just using removeable storage.