what's the difference with PPAs?
the main reason i always fall back to Ubuntu is bc everyone has a PPA for it. Sometimes the PPA also works for Debian, but its 50/50 (from what i understand its not an official thing under Debian?)
AppImages have aleviated this.. but appimagelauncher is broken under Ubuntu and theyre annoying to integrate manually
In one case, none -- extrepo carries a PPA for Trinity desktop: https://salsa.debian.org/extrepo-team/extrepo-data/-/blob/ma...
Generally, these are repos maintained by the upstreams themselves, e.g. Docker, Tor, Armbian, Dovecot... my guess (and it's just a guess, I haven't used Ubuntu PPAs much lately) the PPAs are maintained by not-the-upstreams. Or perhaps some of the upstreams are maintaining both a PPA and their own hosted repo.
I've only used AppImages for software I didn't care about every being updated - can they do updates without having to manually redownload the AppImage?
Yes, but not super straightforward: https://docs.appimage.org/packaging-guide/optional/updates.h...