I don’t understand what problem they are meant to solve. If you have a FOSS piece of software, you can install it via the package manager. Or the store, which is just a frontend for the package manager. I see that they are distribution-independent, but the distro maintainers likely already know what’s compatible and what your system needs to install the software. You enjoy that benefit only through the package manager.
If your distro ships broken software because of dependency problems, you don’t need a tool like Flatpak, you need a new distro.
That Apple can get their own relatively narrow platforms to work really says very little. Shocking if they could not.
As far as home use, Linux works fine. Both my wife and father in law use it too and they are not technical. Cannot remember the last time I had an apt issue or any other issue.
As far as snaps being better. Not my experience. I will take a native package any day over this other stuff. Just more integrated and reliable.