you dont need a device.. just the programming skills to make a good app for the current range of smart phones.
most people do not want to spend $20-$200 just to store there cash, but an app adds a layer of security to your phone.. that would work
most people do not want to spend $20-$200 just to store there cash, but an app adds a layer of security to your phone.. that would work
Phone can get hacked, device can not. Would you prefer to use a phone as a cold storage device?
People have google authenticator app but they still use yubikeys.
Use the phone as face recognition device, have the wallet be a small microUSB dongle to be plugged into the phone. Problem solved.