Yeah, because when you move forward or backward you obviously stand perfectly vertical. It was a tip in case he'd actually intend to lean the character.
in a great many games with floating characters there isn't a 'leaning forward slightly to move' thing, it just moves them and it looks fine, especially with spriting limitations such as time and having to remake a good portion of the sprite to get it to lean properly without making it look awkward.
if you -really- want to debate this, there's no way jet boots could work because there's no way in hell a being could keep their feet so perfectly level so as not to move at all, nor would they bob up and down, they'd stay perfectly in one position due to providing enough upward force to keep the object in the air without dropping, finally the person in question would probably lose balance and fall over when trying to stand still, so to keep from doing so (or doing a split and causing massive amounts of bodily damage from the force of the jets in his/her shoes) they'd be constantly moving in some sort of pattern.
tl;dr doesn't work in reality, don't try to apply realism as an argument in this case.