They don't have a moat. They are one of many similar players in the same space, which are interchangeable both to their workers and their customers, and they can only compete on price.
Drivers often work for several of these companies at the same time, and customers will use whichever one is cheapest at the time they feel like placing an order.
At the moment, with so many similar companies in the space, I don't see how any of them could become profitable, especially while being engaged in a race to the bottom on prices (because price is all that customers actually care about; the experience of a guy in a car bringing stuff to your door is pretty much the same with all of these companies).
Drivers often work for several of these companies at the same time, and customers will use whichever one is cheapest at the time they feel like placing an order.
At the moment, with so many similar companies in the space, I don't see how any of them could become profitable, especially while being engaged in a race to the bottom on prices (because price is all that customers actually care about; the experience of a guy in a car bringing stuff to your door is pretty much the same with all of these companies).