Yes and no.
Lords would love to have religions, and especialy rich ones build there temples in his or her region knowing it will bring him extra income.
The more temples the better.
but still an option to tax them or even an option on how harsh to tax would indeed give more dimension, fun and flexibility, like where used with BM.
except they can't build it without him joining that religion in the 1st place. bit stupid for a lord to go around joining different religions just so they can build temples.