The benefits everyone is listing don't really apply if you play the same kind of game over and over. Ie, if you play the same game all day every day like GTA Online and EA Sports bros. You're probably only expanding your brain for the first few days, maybe a week at most. After that, you're not challenging your brain and you're not learning anything new. You might as well be watching TV.
Now let's say you play 30 different games in a year. That's probably better since your brain is going to have to adjust to different things each time. You're forced to think in new ways, memorize different pathways, etc.
But also, this comes down to a matter of time. Let's assume that TV doesn't rot your brain. And let's say you just sit watching TV for a whole year. At the end of that year, your brain isn't rotted, but have you challenged it in any way? How much more would it have grown if you had spent that year learning different programming languages? So, although TV might not rot your brain, if it keeps you from doing other things that keep it healthy, it's still at least half as bad as if it did.