If they get hacked you will most likely be left with nothing. So if yo get 1% a year that will take 100 years to earn back what you lost.
That is true, but if you look in to the history, almost all cryptoexchanges withstood attacks and sponsored money from their reserves.
And if you get around 4-5% interest on BTC, ETH, it is better than 0 on your personal wallet.