You're right that prescriptivism is fundamentally nonsense, but it's been more than a decade and I still put airquotes on "pizza" when referring to it around Pittsburgh, because I don't want to mislead visiting relatives

I'm Spaniard, I know. The thing is that Spanish omelette is a potato omelette, even though people then add other stuff to the base. They don't call it tortilla de patata, they call it "tortilla de patata y X". The only variances are the density of the omelette and if it has a little bell peppers (or more than a little, goddammit Biscay) or not. Anything else isn't a "tortilla de patata".

I'm not saying that it will taste bad, it just isn't the thing. There are plenty "tortilla de patata y chorizo" and such, but you would never add chorizo or chatka in there and call it a "Spanish Omelette".

I would be surprised to find anything but the basic omelette if I order a "pincho de tortilla".

Regarding the paella, I'm not from Valencia so I won't push back that much there, but I know that usually if you diverge from the standard Valencian paella, you state it in the name, like a galician "Paella de Marisco" and such.

Dude, people claim that putting bacon on a paella is traditional. No it fucking isn't. It will taste fine but it fucking isn't.

I'm sure you have a national dish known elsewhere that locally has plenty variations, but everyone agrees that the basic version is X.