I’m a Mozilla employee too. :).
The Snap build is a partner build that we are building on behalf of canonical, so it includes their attribution for search. It is primarily intended to be used on Ubuntu.
As far as Arch or Debian goes, they have their own versions of Firefox so I’m not sure why they would use the Snap.
We do provide a Flatpak as well which is more distro agnostic.
Hope that answers the question.
Mike