It's as simple as perspective. Since we are limited to our own perception in this given objective reality, we have our own intellectual faculties to work with and no one else's. Communication can bridge that but it's only as good as the tool with which we use, whether language or otherwise
Tarot cards provide a random (I believe) tool for discussion. "Which career should I choose?" If tackled with the idea that the cards are nothing more than ideas presented in a fashion only as ordered as the person interpreting them, it can be a useful tool.
Not in providing "divine guidance" (again, sorry for any adamant diviners around) but for providing another angle with which to see things, with which to analyze the situation.
With the lens of skepticism on, the mind won't consider how this card could be tied into this other facet of their life, it's just chaotic mumbo jumbo
see it as an externalized, randomized thought map. The interpreter and the asker are the two important pieces of the equation, the cards just provide a perspective
The same could be made for I Ching or Pooh Sticks.