We have a bag of peanut flour that I was excited about as it's basically dehydrated Peanut Butter after the oil is pressed out. Then I realized that might not be a good thing.
PB is about 5 calories/gram
PB2 is about 4 calories/gram
PB is ready to eat
PB2 needs mixing with water
PB is 190 calories/30 ml
PB2 is 45 calories/30 ml after reconstituting
Obviously, most of the calories in PB come from fat, while less than 1/3 come from fat in PB2. You would have to consume 4x as much volume reconstituted PB2 to get the same calories as PB.
It looks useful for recipes, not so much eating.