Whilst the Myers-Briggs/Jungian model of personality describes certain mental functions, it can also be used as a set of "eyeglasses" to view the world.
Just as you can use red/green glasses to view a 3-D movie, you can also use the Myers Briggs dimensions as a way of viewing human personality more clearly.
The insight gained can help you to take action in order to improve your enjoyment of work. One example, in this slide, concerns work objectives. The insight gained from Myers Briggs could help you understand what types of objectives would be most enjoyable for you. If so, perhaps you could renegotiate your work objectives with your boss.
On the other hand, if you are a boss, then the Myers Briggs model of personality might help you to understand why it is that some employees don't find certain objectives motivating - even if you yourself find them motivating.
For example, an N boss might provide a broad, general objective, leaving room for creativity and innovation. However, this might be demotivating for an S subordinate, who sees the objective as too vague and unclear.
The insight provided by Myers Briggs could provide a language and terminology that enables the boss and subordinate to discuss how they can set objectives that keeps them both happy (rather than just one of them being happy, and the other being dissatisfied).
Bad Joke: Before modern improvements in communication, half the world didn't know how the other half lived. Now that communication has improved, half the world doesn't care.