Well, some Debian derivatives have been moving to .deb alternatives for the current browser -- snap or flatpak -- which may be the reason for them creating "official" .debs for recent releases. (Experience with the snap and flatpak versions has been ... less than completely smooth for some users.) Not sure that's the case for the ESRs yet.

Yeah but that's not necessarily a good thing. Packaged browsers from a package repo don't have the best track record. I mean they are fine but there's a reason why some want their packages to come from the people who actually made the software especially in this case. Does the ESR Debian package support updates without asking for restarts? Granted it matters less for esr but if it avoids the issue , why not.