All that this does is ensure you don't get stacked with another order ahead of you (so the delivery is direct from the restaurant to the person who ordered) in theory.

It doesn't help with situations where drivers are multi-apping (accepting orders across multiple apps and juggling them). The drivers don't even know you have priority.

edit: and in the US where you can definitely see the tip up front, you will almost always find that the order will get picked up quicker if you increase the tip by the equivalent of the priority fee. But you may well get stuck with a delivery before yours.