I'm not sure "realistic" is important here. It's just art, and watercolors aren't known for being hyper-photographic to begin with. Instead, this enables... while it shows some ability to imitate digitally what watercolors can do on paper, it also shows that it can do things that physical media can't do at all. It's quite brilliant, and I wish it was in Gimp or even Inkscape. Can these images be stored as a sort of "vector"? To be able to go back in and dial down the vortices that you don't like (or to dial them even higher)? To design the water flow underneath as a field of sorts. Would be sort of awesome.