Interesting. The original Myers-Briggs temperaments were in fact ST, SF, NF, and NT. I always thought that was more "symmetrical" than Keirsey, which seemed arbitrarily lopsided. You know what I mean?
Myers called these the function pairs and they're really beneficial for improving communication, since we're taking in information and making decisions through them...Myers also totally emphasized the dominant functions--S, N, T, F--and expanded Dewey's problem-solving model from S, N and T to include the gifts of the Feeling function.
Lots of people use the quadrants (IS, IN, ES, EN) to look at differences in change and at learning styles.
Last two letters (TJ, TP, FJ, FP) correlate with desires in conflict resolution.
Dominants and 8 functions in persuasion, coaching, team strengths and blind spots analysis.
Attitudes (IJ, IP, EP, EJ) work styles. Put types in those groups to draw ideal offices or classrooms and the agreement is pretty wild.
Ideally you'd use all 16 types but in a group session the nuances lose everyone...