I guess the answer is: Because you live in a city and have no stable downstairs to keep a horse ready for riding after you come home from the office... I have seen these machines in Asian department stores, seems to be popular and I believe if it works similar to a "powerplate" machine that the thing will shake much more than an average horse...

If it works as well as all other home training equipment for me, I would call it one bad-ass hall stand.