older versions of software, especially for development, I used to try out new features a lot for things like PHP and other stuff (but it’s kind of a moot point now with things like Distrobox or Nix)
upgrades to the latest major version often breaking because I first moved to the latest non-LTS and then, when it came out, to the newest LTS, contributed by the fact that the PPAs would break, since the devs behind them needed to push a new version for the last Ubuntu release
Today I still wouldn’t use it for their push of Snap, I just don’t dig it, I much prefer Flatpak for my apps