If you have to get an OTP multiple times a day—say to ssh into a prod server—you quickly learn how laborious it is having to take your phone out of your pocket, unlock it, find the Google auth app, find which OTP you're looking for then finally transcribe it without any errors. Pressing a key combo/tapping the yubikey (depends on the model you have and its settings) is much faster.

To me, not having a yubikey would be like not being able to use cmd-C/V to copy/paste and having to use the system menu every time instead.