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.
Bitcoins is good for investment and banks is better for savings, they have different role in our life to secure our assets, for me I have deposit my savings in different banks and those savings are for my future like emergencies and investment in real life, bitcoin on the other hand is better for investment base on the amount we can afford to risk because it has a great future.