As kayoone already said, people usually play games for fun. Knowing or realizing games have some benefit is a bonus. As the effort/exaustion part, people actual

As kayoone already said, people usually play games for fun. Knowing or realizing games have some benefit is a bonus. As the effort/exaustion part, people actually like that. In fact, the tiredness is mainly something people tolerate as a "cost" for all the "fun". When I play sports with friends I'm not doing it to be fit, I'm doing it for the social intercation, the friendly competition. I'll be tired and with some bruises, and will struggle to get off bed the next morning, but I feel it was worth it. Another example, video game related. I like Dark Souls. But I kind of suck at it. During a more frustrating sessions, after some groans and curses my girlfriend naively asked me: "If the game makes you so angry and frustrated, why do you keep playing it? Why don't you play another game?". It made me think. I guess I like being challenged. And the harder and the more times I fall, the better is the feeling when I finally win. The more I shout and swear at the game, the bigger is the smile after beating a challenge (or the sigh of relief).