You don't need to be intelligent....but life experience...imagination....the ability to feel with other people (connect) makes you better able to understand what the cards try to tell you.
Any "case" might bee seen from different angles, and the clue word (which is the same) can change the message from each side....so if one have good life experience then one might pick the right path...and point it out as an suggestion...but never as a finish answer.....IMHO
I think you never have read about Tarot Readers that win every Lottery....or the Tarot Reader that never have a bad incidents ....or that Insurance Company's ban Tarot Readers from taken Insurance ....or Tarot Readers who solve, and gives verdict in criminal cases.