My first reaction looking at the website and watching the video was "how stupid." Then I started to think about it - my DH has a very odd shape. He is an elite athlete and his waist is around 30" while his thighs are big enough that he needs 36" jeans to feel comfortable. Neither of us really wear jeans, so we each only have 1 pair. The last time we had to go jeans shopping for him we spent an entire weekend trying on every single style of jeans in every store we went into. Finally, on what seemed like store 1000, we found a pair that were wide enough in the thigh to be comfortable, but not so big in the waist that they bunched up on him with a belt. In his case, if these "smart" leggings were around half the price, or if he wore jeans more, they would be worth it.
*I know they are now making a brand of jeans (barbell maybe?) that are for athletes and are supposed to fit bodies like his, but if I remember correctly they were around $200 per pair so they aren't going to be an option. To be honest, I think jeans are the most uncomfortable option for clothing yourself. I would much prefer leggings, yoga pants, slacks, dresses, skirts, etc. over jeans every day of the week.