> how [does] making money from money contributes to something worthwhile to society?
I don't have any formal training for credentials, but here's how I've come to think about it...
The markets (of which the stock market is one, but the venture capital and private equity markets also count) are capital allocation machines.
This is easier to see in venture capital. The market for startups makes it possible for promising startups to raise capital. It also "encourages" "bad" startups to die.
It's capital allocation.
Same thing for the public markets. They give companies access to capital (either through debt or equity) at a cost that's proportional to how valuable the company is, or is likely to become.
So society, through the open markets, gives Apple and GE the opportunity to raise capital.
Dying public companies, on the other hand, have a really high cost of capital.
And my favorite way to think of capital is man-hours.
So if you were king, and you were responsible for allocating man-hours to different projects, this is the same problem as capital allocation, and it's the same problem that securities markets solve.
They also provide liquidity and at scale the operational overhead goes to zero.
They also provide opportunities for investors to hedge against inflation, participate in society's long term growth, etc.
But the most important function from a societal standpoint IMO is very efficient capital allocation.