I mentioned my hobby of 3D modelling in my last interview as a demonstration of self education and I got the job which has nothing to do with 3D stuff so obviously I did something right so why not gaming? As it's losing (lost?) a lot of the stigma that it had years ago though I think you'd have to word it carefully to not make it sound like you play games when you should be working. Though I'm not sure I'd mention it on my CV unless, as above it was high level competitive gaming or specifically a role in the gaming industry, but maybe on a cover letter? As it could show you hobbies, while different to the job, align you with a role and could help you get it.