I don't think we should be adding unnecessary fields by default, unless you think it's a very common use case? Did someone ask to sort on such fields?

Considering that we offer multiple ways to index the spatial coordinates, I think it would be acceptable to allow sorting exclusively on the mapping strategy with explicit lat/long fields:

@Entity
@Indexed
@Spatial
public class Hotel {

  @Latitude @SortableField
  Double latitude

  @Longitude
  Double longitude