AppImages as the Main File

Why is so much software distributed as an appimage as it's main file?

It makes sense for a portable copy but if I'm installing a game (osu!) or gaming software (yuzu emulator) on a Linux-based PC, I expect to be able to install it like a normal piece of software (via my OS's package manager or even an installer.

Yes I realize that "installer" is frowned upon in the Linux community but I'm not talking about the decentralized "drop files across the PC" installers that are ever present on Windows.

(slightly different rant but this is a good example)

I'm extremely familiar with the terminal but it makes it so hard to recommend linux when I need to open the terminal to install bloody Audacity. (I swear, if I see another `.tar.gz` file I'm going to scream)

Yes, I'm ranting but this post is just probably gonna die in new, feel free to chat with me and give your opinion. I'd love to see what other people think on this. I realize I may be incorrect here but I'd love to have a discussion on this. I would especially love to chat with someone who disagrees. Maybe I can learn something.