One way to put it is: It's not needed, but it's a damn good waste of time and money!

Even if closed loop is too slow to to the perfect job, it will still help you dial in a better map manually. And I've actually found, after carefulling selecting breakpoints so WOT is spot-on a throttle breakpoint, that a series of WOT pulls in autotune will actually set most of the cells and it will be consistent.

I think WOT is the very least problematic area to tune. Just get it in the ballpark, too rich rather than too lean, and you're set. It's much harder to perfect the rest of the map, considering transitions, mileage and whatnot.