Based on other "ad in store" similar displays I suspect this will go unused in a couple of months, maybe years

You have to sell the media to someone. This is not like the type of self-promotion posters that come with some products, this is a separate thing entirely.

This might conflict with supermarket deals with the beverage manufacturers. It might make it harder to sell some brands.

So either the ad space vendor is aligned with those interests and the ad buyer has an interest in buying this space (which might be hard to justify) I don't see it lasting too long.

Oh yeah and guess what happens if the fridge needs maintenance and is not owned by the store... Something has got to give there.