Trip Advisor is a valuable resource, but sometimes it gets it extremely wrong. One such instance is here.

It costs a few euros to go into the church. I had read some reviews indicating that it wasn't worthwhile; that the outside of the church was the better part of it and also that photography inside was prohibited.

The second point was wrong; it is only flash photography that is prohibited. The first point is also wrong. Again I don't particularly care for religious sites as such but the inside of the church was indeed very impressive in terms of both scale and the workmanship that went into it. You could spend hours in here and still not see every last detail. Of course, we didn't have hours so we just tried to grab a feel for it.

If you're in the town, you should definitely spend the euros and go in.