While I loved the idea and using it a few years ago, it's very hit & miss in my city now. Some are great deals, other places especially restaurants are just using it as a coupon app, and the value of what you get isn't much better than their typical lunchtime deals, but a) you don't get to choose, b) you have to collect in a very specific time frame, c) everything is old/shortdated or lower quality/wonky.
I really wish they would do a bit more curating of the options, or at least do a better job explaining the concept to the restaurants that sign up. As it is, I'm kinda tired of risking paying £5 for a slice of cold quiche and 2 stale cookies eveytime I try it.
What I'm really into is the fast delivery apps (Gorillas, GoPuff, Getir) all seem to be doing similar bags, and because they carry less selection the items are great. I once got about £100 of steak, minced beef, chicken breast and other goodies for £10. Stocked my freezer for a month.