Whatever commodity is most often exchanged for other commodities or for services is money. Cowrie shells, cigarettes, fox pelts can serve as "money". Money is usually portable and durable. Money signifies control over (generalized) resources. Money facilitates apples to oranges comparisons (which grocery store managers must make when ordering). Money facilities apples to music comparisons (which investors must make when directing funds). The dichotomy "money or people" is false, since it ignores the value people place on resources. If you think that's inconsequential, try remain indifferent when you return to your high-altitude campsite and find that someone stole your sleeping bag, tent, food, and portable stove. You're dead, buddy.
You still regard control over resources as a matter of indifference?