I only do TOTP on my phone. The Yubi Authenticator app is a drop-in replacement for Google Authenticator, but it adds significant security because the keys are stored offline in the yubikey and the crypto is done in the fob. Your phone is relegated to sending the time and displaying the OTP, which greatly reduces the attack surface of a standard OTP app.
The actual usage is exactly the same as Google Authenticator with 1 more step (NFC with NEO or plugging in the yubikey 4) to get the OTP.
The actual usage is exactly the same as Google Authenticator with 1 more step (NFC with NEO or plugging in the yubikey 4) to get the OTP.