I'm a big booster on the idea that you can use your hobbies to learn something – practice your accounting helping out a local con, practice your HTML making a website, practice your writing doing anime reviews. Hobbies are a great way to gain and improve skills.
However there's another thing hobbies do for our skill improvement that makes them even more valuable – they provide a kind of mental and emotional buffer to the stress of learning. This is very useful if you've got a lot of stress to deal with or had some negative experiences with training or education