So long as Spain is in the EU this whole thing is a moot point. Catalonia would not achieve independence, it would simply go from being a province of Spain to a satrapy of Brussels. Until and unless the Catalan independence movement is an explicitly anti-EU movement dedicated to taking the region out of the grip of the EU and NATO, nothing substantial would change.
So i don't care either way.
Now Scottish independence, that is something i do support. Breaking up the UK would be an unequivocally good thing regardless whether the movement doing it is left wing nationalist or right wing nationalist.