I have a hellofresh subscription. I'm someone who almost never in my adult life regularly cooked, until six months ago. If I didn't have the subscription, I'd probably have struggled to think of seven different things I could cook that were both healthy and didn't contain to many calories. My subscription means I've cooked about 130 different recipes in the past six months, in other words, I've almost never had precisely the same thing twice. (Although lots of recipes are very similar to each other without being identical.)
All the recipes contain far more greens than I would otherwise have cooked, and I've eaten more salads in the past few weeks than I've eaten in the previous 20 years. Even the white carbohydrates are infinitely more varied, instead of just rice, potatoes, pasta or bread I'm regularly also eating sweet potato, lentils, Bulgar wheat and one or two other more obscure things I can't remember right now. (Cauliflower fulfilled the role, once.)
Initially they were completely reliable, but I have had some problems recently with missing ingredients. I report them every single time, and get a discount off my next order as a result.
Yes there is lots of single-use packaging, that is a downside. On the other hand, it is very satisfying that there is absolutely zero food waste, not one eatable gram of food gets thrown away, ever. (Well actually garlic gets oversupplied, the majority of recipes have garlic as an ingredient, they supply garlic separately to the individual bags, and what they give is more than enough. They can't give exactly the right amount unless they split garlic heads into cloves for you.)
I don't think it would be easy to cook the recipes from scratch. It would be a lot more trouble to source all the ingredients, you would have to value your time at nothing to think them supplying exactly the right amounts for each meal wasn't a big benefit. Even when you had the ingredients, you would have to measure them in use, and store the surplus for other recipes, and coordinate all your recipes to use up all the ingredients. For example, my mince, diced chicken and crème fraiche comes in quantities I doubt you get in shops. I now know that you can't buy "red wine jus" in Waitrose, after that was left out of a recent order. (I had too google alternative ingredients before going shopping.) (On the other hand, if you don't worry about your weight, I suppose you may not care how much of these you use.)
If you think they are just a grocery delivery service, then yes they will look expensive, for the groceries you get. The meal planning and the precise ingredient portions sizes are a huge benefit for me. I've no intention of every trying to cook their recipes from scratch, that would involve a huge amount of extra work, planning and shopping.