Forgot to address J/P more, since that was mentioned.
Its behavioral standalone value is shown in the "brain lateral alternative" theory, where the functions opposite the dominant and auxiliary, but in the same attitudes (Beebe's #7 and 8), end up being "used" (i.e. in a behavioral sense) next after the dom. and aux. and thus even more than the ego-syntonic tertiary and inferior!
1/2 and 7/8 bear the same J or P attitude, and thus might be what we turn to first when the preferred functions can't solve a problem. (The tertiary and inferior are more "vulnerable", and thus "weak"). This seems to be in part what is often picked up by the Keys 2 Cognition test, which measures the functions directly, in terms of behaviors.
Meanwhile, as functional perspectives, the alternatives are still the least conscious.
So this highlights the difference between Jung's theory where the functions are more forms of perspectives, and a more behavioral approach taken by MBTI and Keirsey.