*At what point does almost anything else you mentioned help the business?*

Firstly, it's a market place. The business and investor need to find each other.

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.

    *Everything else seems likes gambling, imho*

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.