I think the answer depends on what you really mean by the question.

If you mean: "Does music have to stay within recognisable bounds and categories, and is it wrong to break those barriers?" most people would say no. This relates both to performance and to appreciation and enjoyment of music - it's very limiting to ignore certain categories or genres or music, or dismiss something because it hasn't got the right label on it.

But if you mean "Is it useful and/or interesting to discuss music in terms of categories?", then many (most?) people would say yes. An analytical approach and an awareness of the different influences and styles that characterise a particular song, tune, performance or musician can enhance appreciation for the listener. I also think that a performer who understands where ths music has come from as well as where it's going will tend to interpret the music with more depth and interest, particularly when the material has links with traditional sources.

So if I enjoy a performance, I can just say "That's the sort of music I like", which is fair enough, but doesn't really allow for much further discussion. But if I can also say, "What I like about it is the way it uses a strong traditional tune and then does this and that with it..." or whatever, it opens the way for discussion and comparison of ideas and tastes.

Using categories, looking at sources and influences, enables us to compare ideas and views of what makes music enjoyable for us, and helps us to know what to expect. I can say, "On the whole, I prefer traditional English song to blues," without saying I will never listen to anything that calls itself blues; I will know that if I go to a traditional song club, I'm more likely to enjoy myself there than at a blues session or, for that matter, the punk-rock night in the pub across the road.

I think some of the acrimony that arose in a related thread recently was because people were confusing these two questions. I don't see that "performance" and "categorisation" are in any sort of competition - to me they are complementary, two sides of a coin.

Marje