Well, it depends on what kind of spiritual work you're talking about. If you're talking about the spiritual work of overcoming the hidrance of the ego-sense, then there's really little tarot cards can do in that respect. It takes hard, simple training of the mind, through sitting meditation, magickal practices, or whatever it is one does along those lines.
However, I think the tarot certainly can orient us towards spiritual realities. Many have discussed the tarot as a map of the structure and organization of the universe, and that's actually one of the ways I find it the most compelling, as a gateway to contemplation of how it all fits together. My current work with the Crowley Thoth tarot is very much centered in spiritual and existential questions.
Further, I think readings themselves can be geared towards spiritual topics. It depends on how one reads the cards. If one reads them more concretely, it's going to limit the number of meanings the cards can have. But I tend to read them more abstractly, which means that one single reading can address the mundane issues of daily life; the larger patterns of my life; the even larger pattern of human lives in general; and the yet even larger pattern of the way all phenomena unfold in the universe, the nature of consciousness and spirit and matter and the relationship among them.
And not only can tarot cards address all these different things, but they can address them all at once! A single three-card spread can suggest to me possibilities for the moods I'm going to feel that day, what's going to happen with my relationships over the next few weeks, and where I am in my spiritual practice, as well as point me to the general nature of the cosmos, which can then point me to how to use the wisdom of that general principle to make better decisions in my life... So the mundane and spiritual issues are intertwined and spill back and forth between and among one another. The mundane can point us to the greater spiritual principle, and the spiritual principle can point us back to how to live out the mundane realities of our lives, which ultimately aren't mundane at all.
When I see a card such as, say, the Three of Swords, I can see it as signifying "mundane" sorrow, a suggestion that I will feel a little depressed or experience some disappointment that day. But then I can also see it as a reminder of the relationship between the mind and heart, and the larger spiritual truth that sorrow and joy are closely interrelated, that there is a core of sorrow in every joyful experience, and a core of joy in every sorrowful experience, and it's all about having an open heart and letting love in. And letting love and sorrow in can be something that happens in a very concrete way as well as a larger, more universal pattern of understanding and responding to the world.
So in the end, it's really just a matter of how you read the cards and what they mean to you, not the cards themselves.
Yuko