"Betters us how?"
Not all research has to be innovative you know. Maybe this doesn't look all that useful now, but it will probably has it's use later, when similar studies use it's results. It might also give ideas to people to start similar studies or write a book or create a religous sect or something. Okay, tha latter ain't exactly good usually, but you never know. My point is that any research that produces some reliable and previously unkown information "betters us".
(As others have pointed out, this previously wasn't unkown to gamers, so the only good thing about it is that now it's scientifically proven. To some extent. People who never played a game once in their life, but skim trough the new issue of their favourite tabloid and read the already half-assed and manipulative article about this research half-assedly will however, have a new reason to fear/hate/whatever games. Yay! Nevertheless this research can still be very useful in further studies.)