Actually in this case I think it still does not deviate from the original purpose.
I agree with this, it might happen that OP is more expose where Bitcoin is being traded in a centralized exchange but nothing in fundamental changed in Bitcoin. Which means that if it happens that centralized exchange fails at some degree, bitcoin can still operate and maintain it's value because it is more likely to operate according to original purpose. There is no middle man or institution in between, only P2P.