Q. Is it effective?
A. That was the sum total of the question in my inbox. I'm guessing they mean is "are tarot readings effective".
Just pure common sense says that it depends on what you mean by "effective".
Is chicken soup effective as a tasty meal? Yes.
Is chicken soup effective as a cure for the common cold? Not a lot, but it helps a little by adding fluid intake.
Is chicken soup an effective cure for baldness? No, not in any way.
So what "effect" do you want Tarot to have?
Some still expect Tarot readings to have the very old-world, earth-is-flat "effect" of predicting the future in exact detail. If that is the expectation, is Tarot effective? No.
If you embrace the more modern understanding...based on probabilities, observed outcome, time as the fourth dimension kind of popularized physics...that your choices create the future, so psychics can't predict the future...in that way of looking at things, is Tarot effective? Sometimes. "When they change their mind, the vision changes" (Jasper Cullen in "Twilight")
If you look at Tarot esoterically then the answer changes again. Tarot is a folk-art expression of common-sense advice, and a creative tool, that helps us explore alternate ideas and solve problems more creatively...if you define Tarot in those terms, is it effective? YES, TOTALLY!
Wishing you a day that doesn't need Tarot's problem-solving.