In general, for bodyweight squats, the instructions are usually to bring your hands in front of you as you go down to counterbalance that your bodyweight is behind your feet. Hindu Squats operate the other direction with the recommendation generally being to have your arms in front of you when standing, and behind you when fully squatted. Why?
My theories range from it making you work harder (because it's counter to how it's generally done) to "it's just always been that way" to it being a matter of that since you're going up on the balls / toes of your feet instead of flatfooted, the weight distribution is far enough forward.