I think it is still early days in bitcoin ecosystem. Ideally exchange should be an entry point and then you move your coins to your wallet. Over time an ecosystem will develop where you can use bitcoin directly or you can trade it over exchanges to other coins. If people are panicking that they can not trade and withdraw USD, then those are weak hands. It is good that big drops happen from time to time to shake those weak hands out. Traders will always be there when volatility is higher. They are not bad as they are helping stress test the exchanges by increased volumes. It is all good for long term health of bitcoin.