Philosophical accounts sometimes analyze motion as a transition between places, or as a mode of leaving a locus, rather than merely the juxtaposition of two completed occupations.
For instance, saying a continuously moving body was here and then there does not fully describe the interval of transition. The kalām formula, on the other hand, aims to identify the relevant difference between spatial states.
These are competing conceptual frameworks. A definition of the nature of motion should not be confused with an operational description used to identify that motion has taken place.