Personally I find it to be a useful model. It's not going to perfectly describe every relationship accurately. But I find it gives me an opportunity to be introspective about a relationship and my contributions to it, including my shortcomings.

Not everything needs to be scientifically rigorous to make a positive impact. Though I agree it's useful to keep in mind the limitations of a given description. MBTI is neat but making it part of a job application feels like a step too far.