Seems sort of, well, dumb.
To be fair I can see other mental afflictions possibly manifesting themselves in a gaming "obsession" but I don't think it makes sense to have a specific classification for video games. Obviously I'm no medical expert either and I'm sure they weighed this decision carefully, but it just doesn't sit well with me as a concept.
I think my perception is coloured by all the stories of teenagers and young adults living at home who's parents don't actively do anything. "Oh, Little Timmy just plays his video games all day" As if they have no power. If it's affecting their grades in High school, take the bloody things away. If they are 26 and spending more time playing League of legends or Warcraft or whatever than looking for a Job, you don't just go "well golly gee willickers we really don't know what to do". It's called "putting your foot down", and it seems to be becoming a lost art for the latest generation of parents.
Heh now I sound like an old person yelling at clouds... Oh well.