The main benefits it has are:
1. The order of the array doesn't have to exactly match the order of the enum for the arrays to contain the correct mapping.
2. Typos in the enum variant names are caught by the compiler because actual symbols are used, not comments.
3. The left-to-right order reads more natural imho for such key-value pairs, e.g. OCLASS_PROC maps to ProcedureRelationId.
