By more than doubling the number of Yelp restaurants Grubhub offers delivery to, the latter hopes to trim delivery fees overall by sheer scale. If drivers are making multiple deliveries in a single trip, it costs less per order, the logic goes.

"I see a point where we could conceivably have extremely low if not free delivery for consumers," GrubHub chief executive Matt Maloney told The Wall Street Journal.

As anyone who's tried ordering from Seamless (which merged with GrubHub in 2013) or another service, high delivery costs sour the novelty of convenience. DoorDash and UberEats have tried to woo customers by delivering Wendy's and McDonald's, respectively, but there's little point in getting inexpensive fast food if the extra costs are as much as the order.