It makes it easier to package and install stuff once and for everyone. And harder to keep your system patched because some software might include older versions of libraries. And you can't just install the patched version from your system repo, because that doesn't apply per design. We also have some minor woes like theming, filesize, integration into the desktop... I think it isn't the best we have right now. I think that is system packages. But that depends on the specific use-case. Yeah. But we need both. At least as of now. Maybe we'll one day get a more unified package format. Or sandboxing for almost everything like on Apple computers. There are some limitations. We can't have everything at the same time. But there is lots of room for improvement. Linux is awesome, though.

i think when your compiling a browser from source its quite easy making rpm,deb,etc or corporations just choose deb then arch users create scripts to convert it to tar.zst then install it

One of the arguments for Snaps used to be that they are available on the sever as well. So one format supports server and desktop apps. Is that true for Flat packs? I honestly don't know.