I have always assumed that /tmp means "temporary". I mean, it's right there in the name. So, a move to tmpfs means "automatic cleanup" to me, which seems just fine, and worth doing for that.
If we're doing because the systemd maintainers say "we have to do it because systemd", though, well...
How long till the systemd guys make package dependencies and installation as a service? You know, sponsored by the IBM/Redhat team, and signed by Microsoft?
signed,
a Devuan devotee