In my opinion, rewards can motivate students to be better in what they do. I think they are beneficial for students and their lives in the future. I remember in my school days, we were collecting stickers that my teacher would give us when doing something right or when getting a good grade. This made us want better grades, so it made us try harder and study more. In addition, if a teacher rewards someone's good behavior, the rest of the students will try to imitate this good behavior to get rewards themselves too. Last but not least, we can say that rewards in a classroom are similar to what a paycheck is in a job. According to this, students learn to be responsible and acquire the logic of the paycheck system.
Of course these rewards need to be age appropriate. For example, teenagers won't try harder to get a sticker. Furthermore, these rewards need to be given fairly and equally to all students according to their work.
On the other hand, the danger that rewards in a classroom bring is that some students might get obsessed with collecting rewards and will only study when promised a reward. That is very dangerous habit because it will follow the child to his/her out-of-school life and create a problematic behavior.
I do reward myself occasionally. For example, when I get a good grade I will eat a snack or a desert that I am not supposed to eat. When I have a long day at work, I will return home and just sit and watch TV leaving the chores that need to be done for the next day.
As a teacher, I believe I use most often the reinforcement style but I do use bribery when needed. I believe that the right way to go is a combination of these too because we want to reward our students to motivate them but at the same time we don't want to spoil them.