When I see post from people talking about some version of UWS or whatever the letters were, it seems to have a lot to do with being arty with words but without really knowing what they want to say. And not just for the joy of playing in the wordbox, which I think most writers have done at some point or another (gods, but teen-me loved fancy words, and the more the better), but more because of a sense that THIS IS HOW IT IS DONE BY REAL WRITERS WHO WRITE FOR REAL! (But in an arty font which is possibly wearing a scarf.)
I believe learning the craft of writing is important, and so is playing around with your own use of that craft, building up enough words on paper that you get a sense of what works for you, and knowing what you want to say with it. So…both what Harry is saying and what he is saying not to do, because there is a marked difference between being original with a mastery of the craft and its options, and doing things in a non-standard way more or less by accident.