Occult is fairly oddly specific and, in my opinion, a little anaemic. Something I noticed in 'Exalted Essence' is that it defines thaumaturges differently from the corebook, calling it out as exploiting occult mechanisms in the world through Sagacity rather than having some intrinsic X factor that allows you to do it.

"Many are the mortal miracle workers practicing alchemy, geomancy, astrology, warding, weather working, and other crafts. Most often, these minor miracles exploit hidden occult mechanisms in Creation placed by the gods or Exalted of yore, accessed by using the Sagacity...