For me i used both, i have bitcoin for my investment and sometimes i used this for paying my bills because there is a rebates in every transaction i made then i have bank account for my savings that i want to earn some interest with it and also for my future.
Having money on banks is good to safekeep them. Unlike now, the price is dropping fast and it's making some large coin holders losing money.
But i do not like banks, it is true that the price of bitcoin is currently going down but still I am satisfied with my money, I have complete control on my money in bitcoin, and you wait a little the price of bitcoin will rise to higher sooner, but banks really sucks, there you will have to pay bigger fees for your money for any transaction and some bigger taxes also.