[fcatalan]

Of course it's just another variety, but it's the one equivalent to the Received Pronunciation or "BBC English". People also tend to consider it the "original" one because, well... the language started in Castile. Up until a couple decades ago, if you wanted to have a career on national TV, radio or as an actor, toning down any other accent and switching to Castilian was a requirement, or at least would help a lot. Nowadays not so much, but still happens enough that in Spain a Castilian accent is perceived as "not having one".