I also assumed every single frame was fully painted (but also thought why, crazy effort.. why not just do it with overlays like the classic cartoonists?)
So still, impressive effort.. but still "first ever painted": What is the difference to classic cartoonists? Just the technique that we call this painting, and cartoonists just drawing, or the more complex pictures, or what else?
My understanding is that they make the distinction on this being painted on canvas and not cells.
But things like Snow White was of course colored using brushes, so it would be reasonable to refer to them as painted as well, although we usually call them “drawn”
Some scenes appear to be fully repainted between frames.