> Now I can run my latest user softwares on a stable distribution. That’s pretty cool.

I'm at a bit of a loss. Isn't the entire point of a stable distribution _not_ having cutting edge userspace? It's an inherently double edged sword.

If you just wanted to mix and match you were always able to run (for example) a debian testing chroot under debian stable. Something like Nix is the more extreme version of that. The point of something like Flatpak then is either sandboxing or the distribution model (ie getting software from the original author).

These days, I’m tempted with Debian stable because of people playing cowboys with software updates, breaking workflows right and left. There’s always VMs for bleeding edge.