The usefulness of a model is determined by its limits.
At the same time, it defines its usability.
A model is a simplification of the existing reality. Take a map, it needs to be smaller than the territory it describes. Otherwise, the map wouldn’t allow one to create the orientation that one seeks and that is missing when one enters the territory the map describes. The map is a tool that simplifies reality.
Models do the same. They do so by simplifying reality and excluding options that are present. It requires the willingness to look at reality with only these options. And it requires the willingness to let go of options that one would have preferred.