I'd prefer them to be mandatory to be honest. It centeralises what a factions have done in the past month, which is great if you haven't been able to keep up with some factions or want to know a certain development. It's also a nice way to measure faction quality and to see how well they contribute to the server. Tl;dr paints a better picture more than numbers on an activity counter.
It also lets us know what outstanding requests there are that the admins should be processing (nerd).
Otherwise, if it does become optional, it'd be nice if factions going the extra mile to do it even if they don't really need to would get a reward of some kind for good performance or whatever.