Good work requires a certain soberness. This comes from detachment. Passion distorts the vision. The emotional detachment demanded by trading is the most direct version of this, and so God keeps it as the most direct way to wealth. The purpose of ārtha may be to inculcate this state: ‘doing what must be done’. That is also the satvic attitude.
I think it relates to the sixth house: cold logic and supporting others. Health must be approached in the same sober attitude. The opposite of the sixth is the twelfth, which includes sex, sin, and spiritual ecstasy– all passions.
