Well, that guy already knew how to paint, so effectively (given enough time) they could paint in any program. It doesn't mean Krita is going to make you paint awesome, or even better than in GIMP, or Photoshop, or Painter, etc... Though, I'll say Krita is a much better program for painting than GIMP is out of the box. Since, y'know, it's not an image editor, it focuses more on the "painting" aspect.
I'll also say I prefer MyPaint to Krita on the free-open-source-painting-apps front, but I have a preference for the lightweight.