[MayeulC]

> The value proposition for experienced linux users who don't do that sort of thing in the first place is next to nil. The only applications that might benefit from such sandboxing are applications like browsers, which have large attack surfaces and might be compromised while browsing the net. But even this is mostly theoretical, not a realistic day-to-day concern for typical linux desktop users.

You are jumping to conclusions here. RCEs are probably more common than you think, and I'd prefer anything that interacts with the Internet to be sandboxed.

Flatpak allows me to easily sandbox Steam games. It provides an easy target to tell user to test against to eliminate distro-specific issues. It allows to run glibc-only software on distributions such as Alpine. It allows me to have multiple versions of a program installed concurrently. It prevents programs from cluttering my home directory, and sandboxing gives me extra peace of mind. As a non-root user, I can also install flatpaks. Ostree also usually makes updates more efficient.

If you use a couple flatpak apps, they are available regardless of your distribution. That helps when working on multiple different distributions.

Use an old-ish debian but need a feature from the latest unstable software ABC? Install ABC as a flatpak, and do not compromise the stability of the base system by enabling all sorts of external, unstable sources.