If it works then it is not Nichush or Darkei Emori. Avoda Zara has nothing to do with working or gaining. Surely, people worship them for gain, but worship means showing subservience in any of the four or specific Avodos, whether you gain from it or not.
Praying to anyone or anything other than Hashem is Assur, though I’m not sure that it is Avoda Zara. To do something for a certain purpose, for which you are told it helps, is not an issue of any of the above. This last category is found in many Sefarim and in many places in Shas.