Why share, not "win rate": Big O splits the pot, so total equity is your slice of the whole pot. A high-only monster can hold less total equity than a scrappy nut-low hand, because half the pot is gone the moment a low gets there. Scoop % (taking it all) is what carries you short-stacked. Fair share is break-even; clearing it is the bar to keep playing. Opponents default to a realistic ~40% range, not random, so these numbers are decision-grade.