1. A lot of people do it as a hobby and not to make money. If you become a "beachbody coach" you get products at a discount, that enticed my wife to pay 40 bucks to join. (she doesn't do anything other than get shakeology at a discount)

2. Their products (aka workouts) are awesome.

If someone does beachbody to actually make money, they will almost inevitably fail just like every other MLMer.