> Some platforms allow you to only use them for handling online order taking and payments (Just Eat?)

Deliveroo allows this too, but frankly I'd happily pay a premium to have those restaurants deliver using Deliveroo rather than themselves, as when it's the restaurant themselves you lose visibility of how far along the delivery is in the app. As a result, for restaurants that deliver themselves that will count against them when I consider where I want to order from.