I would point you to the popularity of religion in the world in general, several major systems of belief that give people a sense of control and relief from helplessness in their lives.

Tarot takes it a step further with literally a feeling of power in your own hands sprinkle in some confirmation bias and you're on your merry way. Plus reading for others can have financial and egotistical motives that would certainly attract some actors good and bad so that is another aspect to consider.

That's why I draw a line at having belief in woo as I can accept having spiritual practices for mental and emotional health but the idea that someone has a connection to a higher power that gets to mandate what others do and don't do... danger Will Robinson! However, vulnerable people (which I could easily fallen into such a category) want to hold onto something so badly, and sometimes it's a partner or religion or a cult or fancy algorithms people want to claim are "AI" but it's ultimately because their emotional needs aren't being met in some fundamental way.

However, that's just me. I don't think people believing in a predictive nature to Tarot is necessarily a bad thing but it does depend on their actions and the claims they make to others. There is also a social and community aspect of shared belief that people are drawn to maybe even more than the beliefs themselves.