I have because I use it for a ton of stuff. Password manager, sudo locally, ssh logins, sudo remotely, openpgp decrypt etc.

It happens sometimes that I forget that's what it's waiting for. I'm no longer on Mac though. I have KDE. I don't always see the key flashing either because sometimes it's buried under the mess on my desk (I know...)

It's a bit annoying that yubikeys don't just trigger a hid event or something, as far as i understand the only way to tell is by looking for some obscure log entries.