But you're confusing what sides of the developer/user aisle you're on.
Yes, there are probably a better distribution for the user to use if they want to save disk space. But Flatpak is not a distribution, it's a delivery mechanism. Are you really gonna tell people "Hey, don't use $YOUR-CURRENT-DIST, use Gentoo instead if you want to use my application" if your goal is to provide value for as many users as possible?
It's simply not possible to ask people to change their distribution because you as a developer prefers a different one. Flatpak is for all distributions, and doesn't require someone to change from what they know and use already, it'll work for everyone equally.
Yes, there are probably a better distribution for the user to use if they want to save disk space. But Flatpak is not a distribution, it's a delivery mechanism. Are you really gonna tell people "Hey, don't use $YOUR-CURRENT-DIST, use Gentoo instead if you want to use my application" if your goal is to provide value for as many users as possible?
It's simply not possible to ask people to change their distribution because you as a developer prefers a different one. Flatpak is for all distributions, and doesn't require someone to change from what they know and use already, it'll work for everyone equally.