You can't use their dependencies or you'd need to provide builds for different versions of the same distro (because many many many libraries aren't that stable, and distros typically only provide one version of each).
And you probably don't want to run your own repository (and I'm not even sure apt can do repositories with a login, so you'd be making your game available to everyone with the link), so you can't use their update functionality either.
So then all you have left is a bad archive format - essentially a distro-specific .zip that's more annoying to build.
The other tools ship dependencies with the program, so they don't have this particular issue. AppImage and Flatpak are also cross-distro, while snap is tied to Canonical and awkward on other distros.