Board Thread:Character Discussion/@comment-3095286-20170121174428/@comment-24426880-20170122205657

The Goth Kids may have only had three episodes focusing on them (Raisins, Ungroundable, Goth Kids 3), they also served plenty supporting roles in episodes such as F'd in the A, Mysterion Rises, TMI, just to name a few. They served several other supporting and speaking roles too.

And in South Park terms that is enough for them to be, not so much as important(because you're right they serve no real relevance to the show's story), but reoccurring ancillary characters in the series overall. Which is enough for them to be classified as minor supporting characters, like Towelie, Mr. Hankey, and others. Who serve similar roles. All of which have higher prominence than PC.

In terms of recent seasons however, if you want to go by that, they're pretty much background characters. And are not even close to being as important as PC Principal.