With washout the incidence line between the leading edge and trailing edge has a negative angle at the tip compared to the angle at the root. That reduces the tendency to stall at the tip. Crow does exactly the same thing, but using hinges instead of twist. But the difference is not built in...it can be controlled, and it can be much more extreme. Therefore it not only reduces tip stall, it can also increase drag in a very safe way, since the tips won't stall.

Jim