I went there last week, as we were on a different tour and had some time, we stopped by and we had enough people to get a discount.

As cathedrals go, this is okay, the art is all over the place, from brilliant to downright awful. As to the architecture, it's standard, nothing to write home about, but it is a major stop on the Camino, so that's why it probably got inscribed.

Does it actually DESERVE to get an inscription, probably not, but it's an old cathedral and UNESCO likes that sort of thing.