I don't think that playing various video/computer games are a bad thing for children. The negative opinion about them is very widespread now but it's not fair in many aspects because not all games are really so harmful for their psyche and besies it's the first of all a problem of their parents', I mean how they care and control their child's activities.
Many of such games can be used not only for entertaining but also for educationsl purposes, such approach is often used in some schools too. Of course parents must control how much time their children/teenagers spend with gadgets in general and what are their activities during this time. For example, keylogger software https://www.refog.com/
can be effectively used for this, it's very useful for monitoring their activities on computer/net and controlling general amount of time for playing such games.
And of course children should have many different hobbies/activities, not only the gaming addiction.