Again, a bigger pain in that ass than browsing through an Online shopping App or website that already does those things, or going to a physical store and getting the same promotions suggestions from sales persons/cashiers? i don't think so.
Hold up. What kind of grocery stores are you going to that
have sales people on the floor or cashiers trying to pump goods? I think I've been approached shopping by an employee trying to push something like... twice in the last five years, if that. And I've generally been the one shopping either for myself or my family for a while now. Most I've
ever seen from a cashier on that front is asking about rewards programs of some sort, and that's almost always been less time and trouble than getting rid of a pop-up.
A, singular.
I'd definitely say ad wise, an online system is going to lose out
hard on the nuisance front if they're working ad revenue at all. If there's a grocery venue that has that as even a notable thing, never mind a sufficient amount to be a concern, I've never been inside it. And, again, I food shop fairly often, and comparison shop occasionally, too -- I've probably been inside most sizable food selling businesses (and a lot of small ones, too) within a good hundred miles of my home, at some point or another. Maybe even further. Definitely further for less thorough coverage.