As an awesome alternative you can use a Trezor (or KeepKey) with https://github.com/romanz/trezor-agent https://github.com/romanz/trezor-agent for GPG and SSH.

As an awesome alternative you can use a Trezor (or KeepKey) with https://github.com/romanz/trezor-agent https://github.com/romanz/trezor-agent for GPG and SSH. Unlike the YubiKey, with the Trezor you have have to enter a scrambled numeric PIN to use it.