The only reason he uses it is to annoy McKay because his legacy system is forcing poor wifi standards in Atlantis.
It's worse than that. Ancient tech, for all its amazing capability, has architecture that is outright hostile to Ghz frequencies. Cell reception and wifi quality are just miserable on Atlantis.
He upgraded it with Ancient tech and now it only plays that one RPG that has Geldar and Hallona.
My first thought was Brain Age. But he refuses to hold the ds like a book as the game requests, hence his look of concentrated concern.
The same reason everyone uses mobile devices. Jerking off on the toilet during company time.
Professor Layton and the Unwound Future, because he's jealous that SG-1 gets to go on all the cool time travel adventures