Money on a Bitcoin wallet are untouchable. The only way you can lose is if Bitcoin loses value but you don't have to worry about theft.
But bank offers insurance to our deposits, that's their advantage and you'r money will not lose its value since you'll not be affected in volatility unlike bitcoin and other crypto assets. We can actually use both bank and bitcoin wallet and it should be defending on our purpose, for me if safekeeping bank is better but you need to ensure you'll not gonna save all your money as you might regret when it's affected by inflation.