The worshipper of ______ trait is practically the easiest to gain and lose. I would not worry about it at all. The education the FMs get is much more valuable. Just be careful, as soon, they will gain a bunch of atheism-related traits. (I love how EB ties intelligence to atheism . But seriously, no sarcasm there)

But anyway, yes, I would like someone to tell me what it does. I checked the EDCT but there seems to be nothing there. I do not really see who having an FM who has the worshipper of X affect his governance in a city with Y temple.