In 2017 if you bought BTC at $700 you had almost 3x profit. How is 4% interest better than that?!? In 2019 and 2020 BTC will make at least 5x profit starting with the current prices. So for me there is no point keeping deposits in banks for interest. I also had 4.5% interest but widthdrew all of it to buy bitcoins in the Summer of 2017.