Existing Wording
Value sets that define their own codes are effectlvely providing inline code system definitions. These are intended for small, simple code systems that are found throughout the implementation context (e.g. lists of wards, status codes, enumerations).

Comments
It seems that inline definition is useful in cases where the semantics are significant in a limited scope-i.e., for local values-and that this is the requirement
that drives their inclusion. If so, this should be explicit. If not, the rationale should be made clear.

Grahame's Comments
Happy to extend the definition to mention appropriateness for a limited scope