Apple Watch Second Factor Authentication?

Follow these directions....https://support.apple.com/en-us/HT204915

I don’t think you can assign your Apple Watch as a trusted device to receive authentication codes if that is what you were hoping to do. Because it shares the phone number of the iPhone the code is received and handled by the phone but not forwarded to the each. Or at least... I have never seen it happen for me in the 18 months since I purchased my watch.