For sure that's not the best solution for spending time. Children are formed their habbits faster that adults, I think you should pay your child (children) attantion on something else: sport, drawing or something else. I like to play different games, exspecially I like to play slots http://moneyonlineslots.com/slots-by-themes/cleopatra-slots/ this is great way to earn some cash and spend your time well when you'll go to work.
Definitely, yes. I became a gamer a few months ago and now I feel significant improvements. I noticed that my memory and concentration became much better and that made it easier for me to prepare for exams. Also, my dreams became much brighter and more distinct. Apparently, my creativity has also improved. But it's possible that not all types of games lead to improvements. I doubt that. for example, standard time killers (like runners) will be of much use. Personally, I prefer strategies (like Civilisation), point-and-click games (like The Room), and building sandboxes (like Realmcraft).