Tarot and other occult divination systems pretty much work on similar principles — they are a representation of the energy forces that are at play in your life at that time.
For example, in Astrology, this is seen via the movement of the stars and planets across the skies. In Numerology this is seen via the prevalence, repetition, and yes, even the absence of particular numbers in your life. And in the Tarot, we see them via the images and imagery present on the cards that we pull out during the reading. Tarot can predict what could happen based on your present circumstances. And it can show you what action to take now to manifest your goals in the future.
Ultimately, all of these methods work if you trust the process, and if the person doing your interpretation is qualified, genuine, honest, and knows his subject properly. Regardless, since they are human, there is a margin of error though rarely, and so no process can be 100% accurate always.
But, by and large, the Tarot Cards can and do talk about the energy forces, situations, and circumstances that are at play. Therefore you should see their wisdom as a guidance or an indication of the events that are most likely to occur.
Trusting or not trusting the process is ultimately up to you. Everyone on this earth has a free will and therefore every single person here is free to choose what they believe in. As far as someone is not forcing their thoughts and opinions on others it does not matter who believes and who doesn’t. Your belief in tarot is your own choice. Live and let Live is what i believe in.