Yes, they can be extremely potent. The religious promotion is pretty nice but the loyalty one is fun too. My last game I wasn't going for tourism but I had some faith going on at the end of the game so I slotted the card where you can choose the promotion for fun and bought a bunch of Rock bands with the loyalty promotion. Ended up flipping three large cities on my borders. They flipped to Free Cities but if you were playing Elanor I guess you'd just end up stealing the cities right away. Well, I mean... that kind of "strategy" comes so late in the game that it doesn't matter *really* but it sure feels powerful anyways, haha.