Nice idea. SeedSigner has a lot going for it. Open source, DIY, minimal, python code, communication via (animated-) QRs, Seed QR and Multisig options.
SeedQR support (with import and swipe) can also make paper wallets and vouchers for Grin a good possibility.
@mcm-mike made a proof of concept for a Grin paper wallet in 2019, but loading from QR is needed to make grin paper wallets easy to use. SeedQR could be the way to implement paper wallets and vouchers for Grin.
One warning though, SeedSigner is an excellent HW wallet, but physically it is less safe than a hardware wallet with secure chip.