It's fortunate the Binance event turned out to be only a rather long outage, and not something worse. But this is yet another lesson for us to withdraw most of our crypto assets to wallets that we control. And leaving at exchanges only the amount we plan for short term trading.
Admittedly there are the cost and time factors. The transfer fee at Binance for ERC20 tokens are significantly higher than Bittrex. It's like Binance intentionally doing so to discourage clients from withdrawing.