"Right, so stall is down to angle of attack?"
"Yes."
"Where's the angle of attack indicator in the kind of aircraft you'll fly?"
"Ummmm..."
"OK, so take a PA-28... you can paint a line on the column.
Keep pulling, you see the line, that where's where it stalls."
I'm not sure I see the relevance of this as one considers whether an airflow-based angle of attack indicator is useful in slow flying an aircraft such as a Super Cub.
The other thing, of course, which a suitably calibrated AoA indicator is useful for is to help achieve both best angle of climb (close to the aerofoil's max lift angle, a few degrees less than stall angle) and best rate of climb. The AoA for best rate of climb will also be very close to that for best glide, helping you to eke out maximum distance in the event of power failure. While the
airspeeds for best rate and best angle will alter with factors such as weight and density altitude, the Angles of Attack will not. Once again, in these cases airspeed is merely a poor proxy for AoA.
Admittedly, for the majority of light aircraft, used mainly for touring and in which the low speed / high angle of attack performance is neither critical nor often explored, an AoA indicator is probably a distraction and a confusion to most pilots who don't really understand the importance behind Angle of Attack and who couldn't really care less about it. But I'm not talking most aircraft, I'm talking a 150HP Super Cub which is designed to be flown in this very flight envelope. At present I have no instruments to aid me in doing so. An AoA indicator would / will.
QDM