I do think personality tests can be useful at times, but too often they are seen as the tell-all or the "true" reveal behind the curtain when they should be used as tools for transformation. They should be viewed as temporary ropes that help us get unstuck—so we can continue moving.
I do think the Enneagram is a better tool in this regard as it is more perscriptive whereas the Myers-Briggs is more descriptive.
That being said, I felt like the Enneagram pulled me out of a certain darkness only to leave me stuck again because I started to identify too much with my results. (Not so much a problem with the Enneagram but my approach to it.)
A rope is only useful for crossing a chasm if you let go of it at a certain point. If you hang on too long, it just takes you back to where you started again.