Good or Bad idea?
Is working out wearing a sweatsuit help us to lose weight more? Is there benefits wearing a sweatsuit?
It makes you sweat more water out, so you temporarily lose weight, but you don't burn more calories than you would without it. Also you gain the weight, you lost because of the suit back as you drink something.
The only benefit I can imagine would be keeping your pores fully functional in eliminating toxins, but you must be careful to drink enough fluids to not hurt yourself. Other than that highly theoretical idea, the rest of the supposed benefits are just scams to sell you stuff for a quick(er) fix.