The risk is to lose part of all of your money. However, I have discovered that this can happen also to your FIAT money that you keep in the bank, or making investments which are popular in the mainstream media. So all things considered I prefer the risks inherent with Bitcoin
It's not really true, FIAT money will only lose its value if they have been degraded by the central bank that controls them. Physical money's value stay as it is and it only matters if the country has a high GDP per capita, which should result into a high cost of living.
Moving it into a bank guarantees that it will earn interest. However, only big savings will result in higher gains and vice versa. Add to the fact that you don't have full control of the money that you will put into it and if you're not prepared to wait for a long period just to withdraw all the interest and capital, goodluck in sorting things out with the bank.
While with Bitcoin, even though it is very risky, there's a big chance that you'll earn higher interest compared to financial institutions and in a short period of time.