The idea of the HOLDER: Secure payments combined with high functionality. You can't pay with Trezor for high street retailers because your hardware wallet don't have internet and camera to scan QR code. You can pay via Coinomi, but this is not secure if you use closed source wallet (Coinomi do not share their code to review) and using not secured device. Hodler is combining mobile payments with security, it's unique value of the our idea.
RE: Cryptocurrency payment terminal for high street retailers - "Retailer Mode" in HODLER Wallet