I don't know how well it works for others, but discovering MBTI and applying the basic principles kept my marriage from dropping dead!
I finally could understand my ISTJ husband.
So regardless of whether I was mislead or not, it worked for me at an important time in my life.
"No ray of sunshine is ever lost, but the green which it awakes into existence needs time to sprout, and it is not always granted to the sower to see the harvest. All work that is worth anything is done in faith." - Albert Schweitzer