There’s a reason for this, they want you to download the app because you’re paying for that coupon via primary access to your personal data. Dominos isn’t just a pizza company, for a long time now they have been a data broker too.
Which I guess isn’t surprising, everyone and their mother wants to be a data broker today. It’s a good reason not to install any apps from anyone though.
Maybe this is a regional thing, but every pizza place that I’m aware of which delivers requires the delivery driver to use their personal vehicle… and does not reimburse for wear and tear.