I think it can be very important. As a Bach Flower Therapist, I had a client whom I knew instinctively that his problems came from his denial of his sexual orientation. But my instinct can be wrong. I can't treat and help someone heal if I am wrong... I asked him. He denied it.
But with both instinct and cards, I can be pretty sure of where I am going. The cards told me my instinct was right. So I treated him with the remedies that allowed him to accept who he was and not feel guilty about it.
When one is dealing with a client, or a querent, one has to get to the bottom of things, or else we are doing them a disfavour.
As to tarotbear's post where he says that one must never use the cards to diagnose an illness! Why not, for heaven's sake??? I can understand that in America people get sued left right and centre for things like that, and that this is a big deterrent, but there is nothing MORALLY wrong in diagnosing illness. The origin of illness is usually emotional then mental, (I will go one step further here and say "always" emotional then mental.) By diagonising an illness, one can get to the root of the problem.
As to legal or financial advice. Well, there are more and more people in the financial field (maybe not in America) who actually go to tarologists for advice on financial dealings. If the Devil comes up in the Advice position, GO AND BUY THOSE SHARES!!!! (And give me a commission, please.)
The Tarot also gives better legal advice than most lawyers.
But the trouble is in the United States, you have your hands tied because everyone is always suing everyone else. We don't have that problem in Europe and I pray to the gods that we will never have it.