System packages: not viable for the majority of packages because the distro devs don’t have time to manually package everything
AppImage: even worse integration (like no desktop shortcuts on install). Developer has to guess what libraries need to be included and which ones are already installed by the user. No sandboxing. Probably worse SLSA scores.
AUR: even worse security. No sandboxing. Packages are often compromised by hackers.
Let’s look at the alternatives: