Technically possible to "cashify" btc?

I could be wrong about this, but it seems like one disadvantage of bitcoin is that it isn't as Portable as fiat cash and would require network connectivity.

Is there any way this could be circumvented technically?

I'm not a technical person, but what about printing a particular QR code on paper that could be carried like cash and then given as payment for later scan/verification.

Would this require some sort of embedded "smart contract" function in the paper?

Maybe this has already been thought about or had already been accomplished?