It also stops you once it correctly identifies the drawing, even if you're far from done. If it incorporates that into its training, then it'll presumably learn to figure out what you meant earlier and earlier.

It's interesting to consider whether it would end up making guesses that it sometimes gets correct, or whether it would actually learn to discriminate based on very early stages of drawing. It's conceivable to me that people might start out drawing "police car" differently from "car" in some subtle but detectable way, even if it doesn't involve what we humans would consider to be the distinguishing features of a police car.