I don't think any of us stated it's essential to have an intra shake. We merely stated it was optimal for us. I don't know how you train but I train hard for 2 hours so it's very beneficial for me. Obviously you mentioned that about longer training sessions so I am not disagreeing with you. You are spot in in stating if someone is training hard for 40 mins it's not really needed. Nor is it needed if they play about with weights for 1 hour. Although if those guys get results from using them we are no one to say they shouldn't.
It's not about how many calories I burn but sure it's a lot. In regards to recovery there is a night and day difference for me when I use intra shakes from not using them. Even if I have a huge post workout meal when not using them the difference is apparant. I guess calories can come into it in one way for me though. If I am eating say 5000 calories in 1 day if I have 1000 of them whilst I train it makes it much easier. I train so hard as well that by the time I walk home I am actually hungry even after drinking a lot of calories whilst training. If I don't have an intra that could mean 1 big or 2 smaller meals extra for me to get the same calories in so it's definitely easier for me utilizing intra shakes.
agreed. it's not about "how many calories you burn." It's about creating an anabolic environment for growth. i believe milos calls this the "hyperemia advantage