They have a long history of being proscriptive for anything that isn't "their real spanish" (that being of Spain). In latin america, we use a lot of neologisms ("commitear", "pushear", "mergear") and those are strictly "prohibited" by them, to the point that some spanish universities, following RAEs recommendations, fail students using them.
Any centralized institution that is in charge of overseeing a large and diverse number of countries that have evolved spanish over the past ~400 years is, in my eyes, set to fail.
Now, I do use RAE all the time to check definitions, but I see it as a "descriptive" body, in charge of creating some definitions. But even some of those definitions have to be "scrutinized" and can't be literally and blindly trusted. For example, check the definition of "gitano", which has a clear pejorative connotation. That is not wrong, is just the reality of how the "spanish speaking world" expresses itself. But should you take that definition by heart? I don't think so.
This is a clear example of "The Cathedral vs the Bazaar", as in Open Source vs privative software. I'm a hacker, I prefer a bazaar to a single institution dictating how we should talk..