This is a popular and useful name because it separates our relatively easily recognized subgroup of Cortinarius from the maddening blur of much of the rest of the genus. Unfortunately, it cannot be used in a way that is consistent with ICBN without a huge amount of work and nomenclatorial chaos. Based on genetics, the type species for Cortinarius, C. violaceus, is in a small sister clade to Dermocybe. This means if you accept Dermocybe, then Cortinarius ends up with very few members (C. violaceus and it’s very closest relatives), and every species in the maddening blur that we all know as Cortinarius must be renamed.