Saving money in the bank is different from Bitcoin investment. If you deposit money in the bank it gives you low or no income and still your capital remains intact. But in that of Bitcoin case it is risky because you may loose half of your money within short period of time and at the same time make triple of your money within short period of time. So in all it better to have some of your money saved in the bank for taking care of some things and also some in Bitcoin and wait till the price increase.
This is what I am doing, and I am satisfied with my plan. It would be foolish to put all our money in the bank because not only would it not benefit us, but our money could also be eaten away by inflation. But it would also be more foolish to put all your money in a volatile asset like bitcoin. We can lose everything if one day bitcoin disappears. So, dividing assets into parts and putting them in different places is the best way we should do it.