The selling point is that it is immutable, not that it uses snaps (it does). Fedora does the same thing with Silverblue and IoT. You don’t install rpms, you install flatpaks. You can install rpms, but you’re not really meant to.

Since Canonical refuses to get onboard with flatpak (for now) they use snaps instead of debs, but snaps aren’t the direct appeal.

The whole idea is that you have a core system in a known configuration. Updating the system just means using a different image. If an update fails, then you just roll back to the last good configuration. Bazzite uses this to nice effect too.

There are a lot of advantages to end users and enterprise admins with systems in this configuration.