In my mind it would be super useful, I could sync my photos when my PC is on and when is off rely on my local photos only since my main goal is having a backup of them.

You could do this perfectly with the docker version, so just curiosity here, why not user docker?

Is it because you don’t want to install docker for only Immich? (you could also install other selfhosted server/apps as bonus),

would you be against snap? As someone already mentioned, there is a snap version.

If the important thing is having backups of your photos, there are alternative apps with different packaging formats.

You could make a request for flatpak, I suppose, but you would have to wait for feedback from devs and understand if they don’t have the resources or willingness to maintain it.

Am I crazy or it makes sense?

Imho what makes sense is that, if I’m interested in a specific app, see what packaging formats it has and see how to install it and try it out. Only if I’m having issues with it, or can’t run it on my specific distro with the provided packaging formats, I try to suggest/request a different format.