Wouldn't mind if they are not intrusive in user flow while using the app, unless the user intentionally search for it, they should not be shown unsolicited. It could also be a cool feature if businesses show deals to get customers in the door, turning the experience like a treasure hunt.

Google Maps sometimes shows ads while searching for a bike route, which can be dangerous when on the move. These are unsolicited. Hope Apple can design advertising the right way without violating user experience.