Many teachers love to reward their students for doing a good job on their classwork.
I have mixed feelings about this, and here are some reason why.
Rewards can make behavior and work habits worse in the long run. Simple rewards can certainly motivate children to work harder, but once the reward is gone, the motivation stops. Behaviors and work habits go downhill fast once the children have been rewarded. "Why should I read if I'm not earning a prize?"
Rewards cost money. Teachers don't have a lot of money.
Rewards give the wrong impression. Good behavior is what's expected. Giving rewards makes good behavior an extra effort worth of a prize. It's almost like turning good behavior into a job, with a paycheck as the prize.
Rewards lead to entitlement. Children develop a sense of entitlement for simply doing what is expected. Unfortunately, this leads to adults who feel entitled simply for showing up at work.
Learning is its own reward. Students need to be developing a sense of pride in what they do. That is the true reward! Feeling good about working hard for something is a wonderful feeling! Taking pride in a project done well, or a successful test is a prize within itself.
Despite all these reasons, I won't say that rewards should never be used. There are some children that need that extra motivation in order to be successful. Some children have behavioral challenges or educational challenges that make school very hard. In these cases, rewards should be used carefully.