The word "amateur" has French (and ultimately Latin) roots, literally meaning "lover of". It describes somebody who does an activity out of love for it, not because he is getting paid for it. While that can result in a performance which is less good than that of a professional, it also can result in an equivalent but different result. Many people argue that for example game developers should feel a passion for games, that they should create games because they love them, thus that they should be amateurs. And it is certainly true that a lot of young people with a love of games dream of becoming game developers. Which is at the root of the many stories you hear of exploitation, long hours, and uncertain recompensation in the game industry.
On the player side the opposite trend takes place: Not only do discussions of games from the players' side often have an air of extreme seriousness. But with price money in e-Sport leagues and the selling of virtual items, some players actually are becoming "professionals".
I think that both of these developments are dangerous. Just like I wouldn't want to drive a car that has been designed by an amateur, I don't always like playing games that have been coded by amateurs. Between rushed releases of unfinished games, bugs, and half-baked "wouldn't it be cool if we had this" features, I really long to see more professionalism in game development. Including regular working hours and proper compensation for the game developers, instead of companies exploiting a bunch of eager kids.
Playing games is the quintessential hobby, something to do to relax and entertain, without a larger purpose or financial interest. Turning it into a profession very much diminishes the entertainment value. One of my commenters uses the handle "Angry Gamer", and the internet is full of people like him, constantly angry about games or their fellow players, because they just took those games far too seriously. And as a actual source of income games are a rather bad choice. If somebody would put the same amount of energy that he uses for theorycrafting a MMORPG into lets say studying engineering, his earnings potential would become much higher.
Thus I would say that games should be created by professionals, and played by amateurs. What do you think?