In my opinion creativity like this is an excellent reason to paint. It can seem as though the painting is "making itself". It is such an exciting way to work because anything can happen: the painting could be heading for the recycling bin or it can suddenly come together and turn into something more amazing than anything I could have planned. I've usually been so engrossed that when it is finally complete I step back to have a look feeling as though I've just surfaced, slightly disoriented having been submerged in a parallel universe. It can feel as though I'm looking at the work for the first time.
We adults should make more time to play. The lesson that these experiments teach me is that the simple act of playing and giving up control allows greater creativity.