This moment is an exchange that allows users to understand that their physical body is directly connected to the computer and how it reacts.
6DOF Input Is The Secret Revolution in Computing, Not VR.
Robbie Tilton

Exactly, this moment is as magical as the first time somebody tries VR but it is different. Putting the HMD gives the realization that you can be teleported somewhere else entirely, giving presence. Getting the controllers matching your movement is giving agency.