I don't think it can be called cash since no one is going to accept it.
Like it's so stupid, even if the other person were to accept bitcoin or whatever they'll still need to verify if the address contains crypto or not and whether the private key is valid (both of which needs internet access on some electronic device).
Have fun being poor. When BoobaCum replaces FIAT currency in 2023, I'm going to get rich quick while you peasants continue to eat mud.