I’d say it adds gastronomically quite a lot to the dish and would say its sparsely used by places because they don’t want to spend much on fresh basil. I’ve been to Naples, several times, and have yet to encounter a Pizza Margherita that lacks basil (the plain cheese pizzas were usually called something like “pizza al formaggio”).

If you knew the history of the Pizza Margherita, you’d know the basil is an important aspect, particularly to the guy who invented it

You’re missing a key ingredient- basil.

The Italians have basil on their margarita pizzas

Well they’re wrong considering a margarita pizza has basil and if we wanted to get even more uppity, uses a specific type of tomato and mozzarella cheese.

That’s just a cheese pizza, m’dude

Wouldn’t it then be called a Currywurst?