Normal cruise in a Cub is just about slow flight in anything else, and wrapping the high-drag airframe into a steep turn scrubs speed in a hurry, taking the airplane near stalling angle of attack
. While a Cub has a docile stall, doing so when the ball isn't centered is an invitation to a rapid roll-off and steep pitch down that may take more altitude than is available for even the best pilot to recover.
This is especially true without engine power or sufficient airspeed above the wing's stalling angle of attack
to enable the steep turn.
The transducer, however, moves in a graduated manner and is able to calculate precisely how close the wing is to its "stagnation point" or stalling angle of attack
, unaffected by aircraft weight, wing loading, gear configuration, air density or slip/skid.