The problem with instant exchanges is that they don't have much variety. Good for bitcoin, eth, and ltc but for everything else we need exchanges. CZ said his new dex will support hardware wallets so looking forward to it
All exchange are vulnerable and cannot be said that they can keep your coins safe for a long term. Many exchanges have been hacked as a result flaws find around the exchange. Hardware is the ultimate and will keep your coins safe and secure without any security breach except information link by the same individual.