The manual lever has a number of uses even with AD. Clearing floods comes to mind, and it's also useful under certain conditions that happen when the engine stalls against the compression stroke so quickly that the auto decompression mechanism can't engage.
The guy who said he needed the lever even with AD doesn't understand how it works. With AD, you bring the crank up against compression, then reset and kick from that point. You don't want to advance the engine farther because you'll pass the ignition point and then have to kick it through two complete revs to find it again.