The purpose of mbti is to create roles that we all understand.
But why are roles becoming important now?
It's because we are moving from a society based on the literate individual to a society based on electric roles.
Print gave us the literate individual and electronics like Central are giving us electronic tribalism. And in any tribe there are no individuals rather each person plays a given role.
And the roles are given and immutable, quite like the roles assigned by mbti.
To the literate individual, mbti makes as much sense as astrology, but to the emerging etribalist, mbti makes complete sense as the assigner of roles.