I've tried a few meal subscription services but recently quit them. I suggested this exact thing back in some other post.

Pros of meal subs
+ Exact portions - I dont have to buy a whole tub of something to use a pinch of it
+ Saves time shopping
+ I try new food and recipes I wouldn't have otherwise

Cons
- Expensive (shipping, packaging)
- The packaging is wasteful as hell. They need to add extra to protect from spills, bumps, and to keep it cool.
- Sometimes I dont feel like spending an hour cooking but I'm locked into the subscription and the food will rot if I dont make it fast enough. Ultimately the reason I quit. I threw out an entire recipe more than once because I didnt get around to cooking it within the 3-4 days and it went bad.
- I'm single and the smallest option you can get is 2 recipes a week (4 portions). It was really too much and I just wanted 1.

The supermarket idea should be cheaper, have less packaging, and you don't need a subscription. Plus most people are still going to go to the store for some stuff regardless so its not like having it shipped is really saving me a trip.