I think any age is fine as as long as the games are age appropriate and there is a time limit for the kids - say 30 minutes a day or whatever the parent thinks is right. There are a lot of benefits if the video game format is used properly. Hand-eye coordination is one, problem solving is another.
Another benefit is that a child can learn the lesson of "practice makes perfect." I used this all the time when my kids were young and they had trouble mastering something. I told them "it's like when you started playing Mario, remember how you couldn't get a level and you kept at it and finally got it done." They could easily understand that illustration.