Comment:

Is Instant necessary as a datatype? I'm not sure why the Instant datatype is not just a "simple restriction" (constraint) on DateTime like the other restrictions in 1.18.0.1.2? I don't understand why use by "systems" rather than "humans" requires a different data type. After all, couldn't the system also use a code, an id, or other data types, yet we don't have extra data types for each of them.