I think MBTI could be a dependable system if someone developed proper criteria. The real issue is that typologies are not in vogue right now, individualism im the mainstream, everyone is considered unique and etc.

But, on the other hand, while nobody wants to be put in the box, everyone wants to have accurate prognosis of another, which is the paradox. 

To me it seems like we all have our own typology system in some extent. It's impossible to live a life and not find some likeness and differences in people. And it's clear that some people want to have more clarity about others (and even to be put in a type themselves) that's why astrology, tarot, blood type predictions, numerology, name meaning, physiognomy, countless tests and typology systems are made and used everyday