Hand any four-year-old a fist full of crayons, and it is a very, very few who don't get busy with them, drawing, coloring, scribbling. I have not stopped scribbling.
If it's just brushstrokes wrestling around, it isn't much of a picture book, is it? There still has to be a picture. And maybe it needs to be a picture of a dog named Daisy or a little girl riding a bike. So I have to be careful before I get too carried away in the manner itself.
Can you really learn to knit from a diagram? Try it. Do you want to learn to ski or surf by yourself? You could drown or run into a tree.
Part of why I like watercolor is that mistakes are visible, and you can't really repair much. It has to look easy. When it comes out, it looks easy, but to get to that point takes a lot of doing.