On a related note:
Decimal/fractional values in x-offset box is really important if the character's in-game horizontal speed is specifically balanced. In the absence of IK, the animation would have to be tweaked according to an x-offset calculated from that so the footing doesn't slide around.
The formula is something like:
time-dependent character speed to be multiplied by deltaTime (pixels/second)
spine "framerate" (frames/second)
Actually, it would probably be neat feature if you could stick the deltaTime speed into the Ghosting panel itself and the x-offset ghosting could be automatically set from it. Dunno if I'd go so far as to request such a feature though. XD
Point is, sometimes, x-offset doesn't resolve to a nice round integer.