I would also argue that hundreds of hours in RuneScape has taught people a lot, from practicing their social interactions, language acquisition, theoretical knowledge, and so on.
I, personally, want to learn a few practical skills in real life, such as playing the piano, or learning how to properly be a blacksmith. These are real life skills that I want to learn, because I think I would enjoy it greatly, but probably will not have a practical application for.
This year, I have been heavily into Dungeons and Dragons, and finally ascended into complete nerdiness by being the Dungeon Master for two different games. One thing I have realised is that, I have learned quite a bit from that hobby, that overall becomes useful at work, and in other ventures.
Just to share something personal, I guess.. A little over 2 years ago, I managed to get so overworked that I got stress-induced panic attacks around the time I bought a house. Apparently, the total sum of stress, tasks, responsibilities, trying to stay ahead of everything, and being in control of everything, made me run straight into an invisible wall, and it had my mind playing tricks on me.
I can say this... being trapped in your mind, and being frustrated over how slow your brain is and how you cannot talk properly, articulate yourself, or convey simple messages is... frightening. Stress is dangerous if it builds up, and one should never take it lightly. If playing a video game, or watching television, helps you to relax and lower your stress... trust me, that is far better for your life quality, than doing something "useful". A quality life has to include fun and relaxation without obligations, because without a healthy mind, you cannot have a healthy body. Without a healthy body, you will notice your life expectancy to drop bit by bit.
On that note... I think this was such an important question to have raised publically though, because what I often felt in my 20ies was that I just had to go at everything at 100% effort, and then I get to rest later. It took me a very frightening, and painful, breakdown to realise... no, that is not the case. I am not advocating complacency in regards to everything, but one should find a healthy balance in life about what to do, how to do it, and when to do it.