I'm not a fan of the data tracking that I know those loyalty programs are for, but at least in the US most stores overcharge you if you don't use them (they present it as giving a "discount" if you use them but really you are just getting the fair price denied to non-members) so you would need to have deep pockets to resist them out of principle.

Around here the main difference is lower pricing on some items, so I mostly just buy those items somewhere else.

I also use one loyalty app only when I get an offer.

Just yesterday I bought some steaks that were $55 with the loyalty card and $130 (no typo) without.

I’ve never seen a difference that huge before.

In my part of the US, anyway, there are several grocery stores that don't use loyalty cards at all, so you can avoid the extortion by shopping at those.

The latest evolution in these are really devious: A shelf tag advertises a price in large print: $7.99 with smaller print "with digital coupon" And then underneath, in the color usually used to show the "non-sale price," you see "$12.99." A lot of people just glance at the tag which looks a lot like the normal 'sale price' tag and thinks they're paying $8. Of course, you have to get in the sluggish, stupid app, and best case scenario scan the tag or the item and get to the right part of the app to "Clip" the coupon. Assuming you can get a good enough signal in that part of the store, and that you haven't become logged out of the app... etc. etc. And assuming you don't make a mental note to clip it in a minute when you get out of this crowded aisle and then forget.

I think they just really want to display one price and charge a much higher one to most people.

If you're paying with credit card or debit card they are tracking you anyways, might as well get a discount for it.

apps are a new thing. before, when it was just a phone number, 867-5309 in the us would usually work to get the discount while being usefully trackable