As they said, the advantage is that you turn faster into the swing.
And Marathon: experienced players do this stepping around exactly because they know that you will have to turn the other side a little. Maybe you could also try to do it? It's also the main reason I die in duels.
I think controlling attack/block direction with keys is the only way to avoid this problem, sadly.
If i could bind them to other keys that weren't my moving keys, I would do that for blocking. Footwork is too important to hand over to the enemy on a platter every time they swing. None of the top duelists use movement keys for a lot of reasons.
I am aware of how sidestepping blocks works, why it works. I can do it, but that does not make it any less stupid.
I Know I am probably just going to ~Deal with it~ but, If I don't even try to discuss about possible other solutions I would be letting myself and others down.