Interesting concept. Not sure about the weight based cost but with that said, I definitely enjoyed the indulgent treat.
I was not walked through the concept but caught on quickly. This is like a salad bar only frozen yogurt. You simply grab a cup and load it however you want. I went for peanut butter and chocolate yogurt with hot fudge and oreo cookies. It was $6.50. Not bad for a loner but I wouldn't want to pay for a birthday party of 12 year olds...