I do think that someone who is skilled at games can provide a better review than one that is not, but it doesn't hurt to have multiple opinions on something from multiple perspectives, either.
In this case, what if I'm as bad at video games as the reviewer, but still enjoy games? Maybe if he likes it, it might mean I might like it, despite not being great at dual joystick FPS games.
Sometimes, when you're skilled at games you forget how counterintuitive/difficult a game can be for some audiences and your review may not accurately reflect whether it's as approachable as you think it is.
I think it's a somewhat safe assumption that most gamers seeking game reviews have some level of skill on par or equal to a reviewer, so most of this is inconsequential, but to say an unskilled reviewer SHOULDN'T be doing reviews or that the reviews aren't VALUABLE to someone is a bit dismissive.
Just know who is writing the review and, if you can, be aware of their skill level in games and take that into account when reading it. If you dislike the level of transparency a reviewer is giving you (no details on difficulty, no insight into their play method, etc), you have a right to ignore that reviewer from here on out, as well.