I mean, it turns out that if we all specialize in one type of labor or another we each become significantly more productive than if we all tried to provide for ourselves as individuals or even small collectives. If we use money as a rough way of storing the value of our labor, we can use that layer of abstraction to trade labor with each other at impersonal scales, benefitting even further from specialization and organization.
I, for one, am glad someone else has gotten super good at growing food and building shelter so that I can concentrate on other things as I desire. I could even become a farmer, if I wanted!
Without specialization the effectiveness of trading labor doesn't go much beyond just doing favors for each other. I don't get much value out of having you do a task for me if I can do it comparably as well as you can. I have to weigh the benefit of having someone else work for me and building mutual trust against the cost of being indebted to someone else and the risk of them doing differently to how I would have wanted. If we each specialize, now other people can offer labor that I can't perform myself, and when they get good enough at their specialty it really starts to outweigh the negative sides of having someone else do the work for you.
Money is necessary if you have specialization. You can't keep track of who has done what favor to whom or how much that favor is really worth. Money is the thing that makes extreme specialization possible.