Similar to any courier in the world. USPS/UPS/Airlines/Uber all of them have the same approach.

Logistics is a non value added process. Moving things around is just a cost. No new value is added to the item being moved. And it takes effort to do so.

The beauty of this system is the the choice is in the hands of the users more than the system.

If you want your delivery to go out fast you pay a higher fee. If you don’t mind the wait, you can pay the lower fee.