The I Ching is very ambiguous and open to interpretation, as Philip K Dock shows in The Man in The High Castle, or you can try for yourself. Whatever else it's doing, it is not providing certainty.
Most long-lived divination methods are very vague. Anything providing concrete predictions is easily proven wrong and discredited, only the vague survives.
But people rarely take ambiguous answers for what they are, and instead interpret them into something more certain.
And this lets divination exploit all kinds of biases. On top of the regular old confirmation bias, whenever the interpretation turns out wrong, people don't write off the divination method, but assume they merely "interpreted it wrong" (and often, the vagueness means they can retcon an interpretation that is true), and worse yet, assume that now they're better at interpreting so next time it's going to be a correct prediction.
Observe how little the personality tests actually say, they're just as ambiguous.
MBTI and most other personality tests unfortunately seem to be astrology for the scientifically oriented.
https://en.wikipedia.org/wiki/Myers%E2%80%93Briggs_Type_Indi...
I look at personality typologies in general as approximations. If you actually want to get to know a person, get to know them. But when you need to make a snap judgment about how someone might see the world and react to you, on very little information, it's handy to have a general archetype as guidelines. You can fill in all the details later.
It's not unlike Carmack's fast inverse square root, a Bloom filter, or how Google hasn't used PageRank since 2006 (instead substituting a cheaper-to-calculate approximation). Yes, they give wrong answers. But the answers are usually close enough that when you lack the computing power to get a better result, they'll do.