Advantages of cash over bitcoin, yes you can definitely use it even offline. You just need a regular wallet, a purse, or just about anything you can put your cash into and it'll sure work fine. Yes, there are no transaction fees when paying through cash, but there are times wherein you will be required to wait in line, sacrifice energy and time just to be early or stay in the line. I guess that would equate to the transaction fee for the instantaneous do-wherever transaction for bitcoin. But I must disgree that credit cards, ATMs and banks may require transaction fees as well on top of the time that you have waited.

I agree that the payment method through cash, credit cards and atms are widely understood by people. But I must say that paper money also has the risk of being faked and therefore not accepted in stores. Worse is if you get accused for carrying around counterfeit money especially in large volumes without you even knowing it!