I want my apps to be able to talk to each other. So flatpak is just in the way.

This is (at least somewhat of) a legit concern. But is mostly directed towards Flatpak's limitations in its current implementation.

Also, I don’t see the point of immutable distros. I could boot off of btrfs snapshots years ago. Immutability gives me absolutely nothing of value either

Have you ever wondered why openSUSE started working on (what would eventually become) Aeon while they had previously pioneered the BTRFS + Snapper workflow with Tumbleweed? I believe you may find the point of immutable distros in there 😉.