I like what Jeff said in this forum thread on tarot cards, which have come up in conversation lately. I think he has a good point:
I think of Tarot cards (and such) as a trying to see meaning within randomness not unlike seeing an image in an ink blotch or an image on toast or an image in the clouds. We see what we want (or need) to see. If we have a psychological need to see certain things, then these devices can help us with this seeing… I would caution that there are probably better ways, though, to make certain important life decisions than seeing meaning in random patterns. But at the same time, some decisions are hard to make and sometimes you do have to just “go with your gut”. Perhaps these devices can help some people “go with their gut”.