Well it's not just painting and drawing, it can be anything creative including poetry or even music/dance. And it's about the process not the end product, you don't have to be good at it technically (I'm not). The advantage for me is it enables me to process things that exist on a non verbal, pre conscious and embodied level. I find talking therapies are too 'in the head' and often tend to go around in circles or overly focus on cognition or superficial modes of processing.