You actually have to release the W key, hit and hold direction key and then hold W again, otherwise the legs won't move, what you described it basially the same, but the leg movement doest kick in. The only usage i can think of atm is the possibility to lock a/d+w in mid air without changing the driectin - comes in hadny when you do for example glide jump into wall jump. Can't think of any bigger cons tho - except maybe newbies locking themselves in mid air after their first backflip, oh well, soldat's learning curve is quite steep ^.-