No, Domino's doesn't actually believe that it's been a major hassle to pick up a pizza and bring it home from the store ("store" sounds more accurate than "restaurant," as anyone who has actually eaten Domino's-Brand Carbs and Sludge can attest.) That's just it's way of trying to get out of the Delivery business because the cost of gasoline is pressing on the old bottom line and the current delivery fee was already inflated. Domino's would very much like to fire all those people who have been making a little extra money bringing you your pizza by turning you into your own delivery guy.
So they'll give you a few bucks off if you'll just come by and get it yourself, and they'll call it a "tip" because you're stupid. How do they know you're stupid? Um, you're buying pizza from Domino's!