But then you usually have to sign as well. Chip and PIN transactions don't need a signature, and in my experience the total time to swipe+sign is about the same

But then you usually have to sign as well. Chip and PIN transactions don't need a signature, and in my experience the total time to swipe+sign is about the same same as insert+pin. Contactless payments don't need a signature or a PIN, so they're significantly quicker.