I don't think it has to have tomato sauce, but I do think it needs something. I even think it's possible to have a pizza without any sauce, kinda like a calzone, where they typically don't have sauce, but you have a cup of dipping sauce on the side. The pizza in the post sucks though. It needs more toppings, or more cheese, or sauce, or something. It's just way too plain.

There are a lot of different ways to make a pizza, especially if you're open minded to trying basically any type of topping on a pizza. Italians or traditionalists when it comes to pizzas might find a lot of toppings blasphemous, but in my opinion, it's a great platform and you can do a lot of creative things to make good food starting with a pizza crust.