I don't believe "关小屋".

My kids' daycare has thinking chair, not in a "小屋" though.

But I think by comparison, hitting has following disadvantages:
1) a bad example, kids learn he can solve problem by hitting. Any one read the basic child education book will learn this, don't tell me those experts are just lieing.
2) physical harm, sometime could be quite bad if a parent does not have the habit of self control.