The irony here is that if you click on the link to the German wikipedia article it will tell you in the first sentence " Europastraßen sind eine Straßenkategorie von Fernstraßen." (European routes are a category of long-distance streets.)
Looks like even Wikipedia isn’t quite sure if they are a category or not.
Personally I’d be in favour of deleting most of the network relations, be that for roads, hiking, cycling… They mostly seem to be there to add information that is only marginally related to geographical information. At some point we simply need to draw the line or we end up duplicating all of Wikidata using OSM relations.