Sigh, I was a sysadmin on my own system from 1999-2008 and on a busy server from 2008-2012... then essentially quit. Now with flatpak and snaps it seems I have no idea what I am doing.
Flatpaks aren't very relevant for servers if I am not wrong but Canonical definitely tties to push Snaps for that usecase, I feel like other container technologies like Docker or Podman are a lot more relevant in that context and containerization in general is really nice especially for server use and not that hard to wrap your head around! ;)
Yeah, that's really what I haven't used that seems significant these days - Docker. I used to use VMs a fair bit including the premade ones from MS for IE testing, which I think (?) are the same concept.
Well not really, Docker dose run another Linux system but on your actual hardware so you don't have the overhead of emulation, it's really cool for a lot of things!
I won't use it myself because I don't think it's a good idea to give Canonical or any other company that much power and don't think it's centralized nature should be how such package systems work but I don't think it's a bad system at all! The sandboxing has it's hurtles but it's really good and I am a huge fan of proper sandboxing so if it works for you it's certainly a good option!