And what about the EASA principle that FCL priviliges may not be prescribed by national law?
EASA itself has already proposed 'where permitted under national law' in other areas. So what is sauce for the goose....
In any case, the IMCR privileges would be universal. But
airspace regulation varies from country to country. National law would limit where the rating could be used in those nations who decide their airspace structure is such that they would only permit en-route IFR (or whatever other limitation they would wish to apply to their airspace).