Thanks to said API, Tailscale on MacOS is even distributed as a sandboxed app through the Mac App Store [1]. Flatpak's restrictions make certain classes of software difficult to use on "atomic" Linux distros like Silverblue or Bluefin that provide a read-only base system and expect users to get their software through Flatpak.
[1] https://tailscale.com/kb/1016/install-mac