ATC
Even using the AOA you will not be flying it to the ground
The question is is 1.3 an accurate margin for all aircraft?
Ghengis mentioned one aircraft where the POH recommended 1.64 as it was a very draggy aircraft where 1.3 was not sufficient.
On the flip side a very slippery aircraft and 1.3 maybe too high a figure and maybe 1.2 would suffice
The AOA is a much more accurate indicator than the Airspeed indicator no one is saying at some point you do not transition from the the gauges to feel and outside references only that at what speed your VREF do you make that transition
Pace