Hi,It does seem to me that avahi-daemon is the more complete mDNS implementation at least at the moment, and that therefore it would make sense for it to be installed on Debian systems that require such a thing at the moment.
Given that, the "Debian's systemd has MulticastDNS=no" answer seems to have the merit of simplicity; I'm not keen on having avahi-daemon installing something to knobble an otherwise-on systemd mDNS system.
Regards, Matthew