For now it is more dominant cash because ATM or bank is everywhere. But if later bitcoin already exist bank and its ATM, maybe people just open handphone and scan barcode to do transaction hahaha 
In the future, bitcoin doesn't even need atm anymore because all can be controlled via smartphone, bitcoin atm in my country didn't get a good response because android makes everything easy, cash money for the future is virtual, not currently so popular because the world economic system still prioritize fiat, many offline shopping also not using bitcoin.
And there is no guarantee that an internet connection will always be available so cash will always be a necessity until this problem is solved. Maybe via trusted physical bitcoins where the private key is hidden and they are hard to fake.
I agree with you because the sustainability of bitcoin is not guaranteed by any group or developers. The cash it spendable everywhere and it's physical so that you can carry it with you not depending on any other external factor.
Bitcoin requires secure internet connection.