Haven't you been to the Camp Nou?
Objectively speaking the Coliseum is probably in the top 2 to 3 worst outdoor pro sports venues in the United States. Relative to the Camp Nou it's a modern palace and they've had a near identical life span.
Camp Nou was obviously engineered to accommodate one specific purpose. Fit as many human bodies as the laws of physics will possibly allow onto a defined piece of land.
There's a certain novelty in that, and like the Bernabeau it's one of the most vertical stadiums in the world so the sight lines are fantastic. But the World Cup is a hyper corporate event and in the context of feasible World Cup venues, it's an objectively worse venue than any American football stadium.