> Appimage is basically a linux port of the windows workflow where you download an exe file from random sites and run it. No update mechanism, no discovery, no install/remove mechanisms no sandboxing.

Not 100% true. See e.g.

https://github.com/probonopd/go-appimage/blob/master/src/app...

Since the AppImage format is always the same and not just a random .exe it is possible to build tools around them.