I think it only adds up for the addiction. I am sure there are some of the users who may find that it does not help intelligence . And instead it makes things a bit harder to notice as well.
Possibly, if you have a really low IQ to start off with. It can definitely increase your knowledge in certain subjects but nah, not intelligence.
I think gaming can increase intelligence in some ways. Well, in reality the game is really different in our world. When you play, you seems drag inside the game and yiu experience different world. In that case, your in character with the game. In that your imagination broadens. You develop creativity in that part. Which is also part of intelligence.
One way it could possibly increase intelligence if it has some sort of subliminal messages within it.
Gamers tend to lose intelligence from what I have seen. Not something that I'd say gaming helping intelligence.