The big difference is that this allows you to make money on a "task" that you're already doing anyway. Remember, you would make deliveries only to places that are close to your home, which is where you're headed. It's only a matter of making a small detour on the way home.
I don't even think it will be about the money. I could see this being a system where you earn credits for delivering, so that in the future, you get free deliveries yourself.