I wonder if there’s a way to make it skip the confirmation step. Apple Watch auth when logging in requires no confirmation, so is there a good reason for sudo to require it?

That would make it faster than Touch ID and having to first click on the authentication pop-up.

It would also allow to authenticate sudo without you knowing for as long as you sit next to your machine

Well, you know about it, because the watch makes an “unlocking” sound and taps your wrist each time it authenticates you.

Right, but there’s no way to undo a sudo authentication.

how do you enable this? Would like to do it for my desktop. Also for application installers if possible.

System Preferences -> Security & Privacy -> General -> "Use your Apple Watch to unlock apps and your Mac"