While I don't disagree, I will say it is hard to eat all the calories needed when you are a hard gainer like me. I'm 6' 6" and 180 lbs, very low body fat. I struggle to gain and the shakes definitely help. I drink 3 to 4 a day depending on what I do and what else I eat.
It is easy to add fats to food. Healthy calories are easy to add to a diet. A little butter, or MCT oil can add lots of easy healthy calories.
Not a lot of protein in butter and MCT oil though, right? I don't have a job that allows me to stop working and eat protein packed meals multiple times a day, but I can easily stop for a minute and slam a protein shake. So, for me, they are beneficial. Btw, I consume a ton of MCT oil... definitely agree that it's good stuff