I added a related link because NYTimes wanted me to get an account and that wasn't going to happen, I think it's the same story and wasn't behind a wall for me.

I notice this on grubhub a lot, our closest Chinese place charges $1 more for everything on the menu if you order through grubhub. So these days I use them to see the menu and then go to the store and place the order and save $5-6, plus no tip or delivery fee, so it's win win I guess because they don't have to share the profit.

It comes down to convenience vs cost. For the frugal or those on a strict budget, this is rarely an issue. For the rest of us, does it make more sense to not have to get ready to go out and instead have someone bring our tacos to us, regardless of the markup? For me...sometimes.