Short and sweet(aphorism- as Mcluhan suggested).
Maybe hard picks aren’t all their cracked up to be, think about it, in forearm Pronation(flat on the guitar-towards full pronation), the pick supinates(on the downstroke), and pronates(on the upstroke) and in forearm Supination(underside of forearm visble- towards full supination), pronation on the downstroke and supination on the upstroke.
This means a V shape between the pick and forearm on one stroke and a U shape on the other stroke- almost impossible to see in forearm pronation but very easy to spot in forearm supination (so called “downward pickslanting” - my preference btw).
So some pick flexibility may be good for making it all happen for aspiring players(as physical suggestion). Just watch Albert Lee in the “compound curve” video.