Thats quite something, I'm super impressed by attaching the fairings to the first stage, would love to know if anyone has ever done that before (other than SPECTRE in You Only Live Twice but in reverse [0])?
It allows them to strip the second stage right back to something much cheaper when it has (at least initially) to be disposable.
This is awesome. Interfacing with the second stage at common hardpoints to the Satellite bus removes a tonne! of mass. Hardpoints and distributing there loads across a vehicle skin end up weighing more than the skin itself. Love it all!