Зато телефон легко можно сломать, потерять, сбросить
А юбикей никуда не денется, если его прицепить куда-нибудь надежно
I use a smart card (NitroKey, YubiKey, etc) to store my private key securely. Why should I use Krypton?
With a smart cards you can generate and store SSH keys in a separate piece of hardware connected via USB. While the private key might not be extractable from the device, users now have to purchase and carry around another piece of hardware that takes up a USB port. Configuration of the smart card occurs on the workstation itself, which may be compromised. When you approve a signature, the only information conveyed to you is a blinking light, meaning you don't know what you're actually signing.