I get that it goes against the fundamentals of crypto currency, but exactly for what reasons though? Assuming you're not using it for anything illegal (if you are then it's understandable), why the concern? I'm asking specifically when trading.
One most probable reason would be unpredictable questions from government authorities in future. Basically I do hate clearing KYC for no concrete reasons. While I am into this crypto space, I prefer straying anonymous hence I do not want to to submit any of my documents just for the reason of continuing trading in reputed exchanges (this way I have stopped trading on few long running exchanges).