The idea is that children will receive a reward which will reinforce the behaviour you desire. And not surprisingly it works. When there is a reward, children will work towards that goal, sometimes even harder than they might if there were no reward. So what’s the problem? Isn’t this great?
One would think that with the evidence cited by many countries and health professions against the practice, the issue would be moot. But (yes, there’s a ‘but’), much of the older research cited has flaws and thus leaves the door open for those who support the practice to stake their claim.