Yes, granting wishes is typically a role reserved for spirits and the divine. To be able to confidently sell the immaterial as a mere human, one must either be incredibly skilled or a very smooth talker. [Kimihiro doesn't seem the type to be a scam artist, though. Way too socially awkward! Skilled seems the much more likely explanation.]

But you know, the line between gods and mortals isn't as solid as one might think. Tell me, Watanuki Kimihiro, if you're born as one thing and you become something different, do you lose that part of your identity? Or can you be defined as both, accepting all parts of your existence?