Personally, I'm favoring it because I've been in a lot of games where it works out really well? And it greatly lessens the time pressure on tagging. It sort of sucks when you have to drop a thread and have to assume out CR or potentially emotional moments, things like that. I could also keep the calendar updated to keep up with what day is what.

Problem is it can get confusing if you just want to assume, "Oh, Easter is this time of year." But we're not using typical Earth holidays anyway.