Oauth is designed as a means of communicating identity between servers that don't necessarily trust each other. This is useful for third-party login scenarios. However, this lack of trust introduces overhead, since the authentication credentials cannot be sent directly. Typically, this involves the use of a middleman (i.e., the user).
Whether this ...
YubiKey Nano and Somu (the small variant of a Solokey) use a capacitive way to detect that a user touches the device. There is a small area of metal that protrudes out of the plastic casing that nearly vanishes in the USB socket.
The user presence detection is part of FIDO U2F.
In summary, the user will have to touch a button to register, and may also be ...
I do like the idea although, I feel you might have missed the target.
I do agree with others on statement roughly telling that this kind of sophisticated mechanism seems to be pointless at client-server authentication. There I would agree with the recommendation to use some kind of hardware token.
...but still there is a room for your proposal