Idk why the correct answer always attracts several down-votes on Lemmy. This is literally it… Money is useful because it can be used as payment, it can be exchanged for goods… The reason why our whole lives revolve around it is because we have shaped society to be that way… We call that capitalism.
(And with knowing the proper term for it, everyone can just look it up on Wikipedia and learn about the history and how it’s all linked.)