This is a fascinating history lesson alright, but perhaps it throws the baby out with the water too? Like all theories it is a model, a simplification, an abstraction.
Are the Super-Ego, Ego, and Id more “scientific” than MBTI? I daresay not, but they have been immensely helpful to the development of psychology as a science and as a practical toolbox for help and self-help.
I can say from personal experience that MBTI has helped me figure out some important things about myself and perhaps even to improve on some counts. It also gave me another perspective on how people are different and made me a but less judgemental.
As with everything else, the “corporate” version can go awry. That does not invalidate the utility of the basic insights.
Take the movie Inside Out as an example: I am pretty sure there are no 5 colored little people sitting in a control room in our heads. But the model they represent gives a fairly good approximation to human behavior and feelings. It can even be used a therapeutic tool. Same goes for MBTI.