a short recap:
Pro's
1. Shrines add gold/science(AV) and mana.
2. Multiple religions allow for multiple temples, freeing up priest slots and adding happiness.
3. Secundary benefits (NN and DD) are useful.
4. Can contain spread of non-preferred religion (AV, order?)
5. More freedom for alignment switching, if you spread the religions properly.
Cons
1. Religion techs require breakers, which could be used for other (military/economical) techs.
2. Some religions conflict (AV+order), giving some negative events.
3. In case of nox noctis: shrine effect could be non-preferred.
4. A huge increase in the annoying "please adopt our religion" pop-ups.
5.
spreading multiple religions costs a lot of
Did i miss any?