If you're scanning the bar code with a phone app, it's just going to use the camera. So as long as the display has a high enough resolution to display the QR co

If you're scanning the bar code with a phone app, it's just going to use the camera. So as long as the display has a high enough resolution to display the QR code and it shows up on a camera, it should work fine. But keep in mind, you probably want the device backing the epaper display to allow some kind of password input and store your BTC key on an encrypted medium (either encrypted flash or an LUKS/ext4 formatted sdcard).