Not great for families. Meal prep does NOT take 30 minutes--as PPs noted, it can take upward of 45 minutes, and I consider myself a fairly experienced home cook. This includes taking everything out of the packaging, washing all the ingredients, chopping, etc.
Also, the amount of pans required for cooking meals can mean that you have 4 burners on at the same time. There is no break, really, in the meal prep. You're always doing something.
The nice thing about Blue Apron is that the meals are tasty, you don't have to shop, and the ingredients generally high quality. I think the meals would be fun for couples who want to spend a "date night" cooking in.
Unfortunately, the recipe developers aren't thinking about the larger context of family cooking. With young kids, it's really hard to spend 45 minutes straight in the kitchen with all four burners on; a huge pile of plastic, boxes, wrappers, etc., that needs to be broken down and put into the recycling bin; and a load of dishes at the end of the night that needs to be washed. I also have a ridiculous amount of Nordic Ice in the freezer that I will never use.