Overall that also gives us ability to have multiple instances of the same app installed multiple times from different sources.

You can't just type this like that while ignoring the fact that appimages also let you do that.

Flatpak is for desktop apps

Yeah and unfortunately I've already seen takes of people saying that snaps are better than flatpaks because snaps are CLI friendly and "why would I have two different systems when one does everything", this was just a bad decision on flatpaks side.

Imo, nixos does what flatpak tries to do much better, and more importantly you can run nix alone as its own thing, while flatpak has to be on top of a existing distro.

Wayland support is intentionally broken by AppImage creator/maintainer just to be able to point finger at Wayland ecosystem and say: look - unfixable.

Link?

Also btw, wayland has been insanely broken for me, this is mostly because I'm stuck with sway as my only option though, I have 4 bug reports still open that came from two days of trying to use sway.

AppImage maintainers also showed their disappointing attitude when trying to get OBS to use it, assuming everyone will be interested in having that package format published on official projects website, while conforming to all requirements and doing the work of adjusting app to that format. To no surprise, OBS was horribly broken when built that way, and they demanded OBS devs to fix it, not getting how could they possibly not be interested in having app image, while already having well built (I use it myself, it’s great) Flatpak package.

I use OBS-studio as an appimage made by a guy that basically wraps the aur package in a junest enviroment. It is actually a whole distro in a small package at this point, the downside is that it makes this appimage 172 MiB. Which is meh. Could be better but it is better than either depending on my distro (I have ptsd from using voidlinux if you didn't know lol) to provide me a obs-version that works, or install the whole flatpak and hope that the obs-flatpak doesn't actually break (and this last step will be way more than 172 MiB due to the runtimes).

Flatpak does sandboxing with fine tuning abilities (using something like Flatseal or new KDE’s built-in KCM) + there is actual verification process at least for new apps on Flathub. I don’t say it’s 100% safe, but compare that to AppImages which is just running randomly downloaded binaries from the web with full filesystem access.

Cool, if only the rest wasn't as bad.