Yes, I think that Mozilla’s new deb package is in response to Canonical dropping the deb package and replacing it with a snap.
It will be interesting to see how may people run away from the Snap version. They could have before by using the tarball from Mozilla, but that isn’t fully integrated like the deb package is.
In addition to that, it could also be a benefit for Debian itself, as it currently has only Firefox-esr in its repo’s.
They are also closing the gap with Chrome a little bit as well. Chrome apparently already has .deb and .rpm packages.
As a Debian user and recent convert of using the Flatpak version of Firefox to have it well integrated as @LinuxUser already mentioned, I appreciate the .deb version and would use that one instead if I do not plan to use the ESR version. The Flatpak version still has some problems apart from only supporting the Adwaita theme and nothing else by default.