The reason why folks must be confused is that, non Stock market gambling is seen as a vice and/or crime by much of human society. There are religious edicts and/or laws against this practice in most places. The Stock Market getting a free pass from this view - and most people (including myself) not knowing about the nature of this system until they dig a bit deeper - seems unfair.
Las Vegas is looked upon as lascivious even when some of the gambling requires skill (Poker / Blackjack) - derivates trading is instead marketed as a great career where the people doing are superheroes.
I’m not bitter about this even if the message sounds so. Just fascinated by the asymmetry of perception.
Then I learned it's all about risk management and absolutely technical analysis trading is gambling. I agree with you, blew my mind!
To create the market place, you must understand that different investors and different businesses have use cases that you don't need, such as "almost anything else" I mentioned.
One of the dimensions is risk profile. Some investors want risky positions in highly leveraged trades e.g. buying a lottery ticket. Some though want a minimal return on an almost sure bet e.g. Italy won't be beaten by San Marino at football.