Just as a thought experiment, would you say there are any (societal) negatives to the possibility of thr price of bananas (or the share price of spacex) being able to fluctuate wildly based on semi-abstract economic manipulations, like shorts and futures and such.

What I'm getting at is when does it go from investing, "I think this entity is going to take my money and use it to build a profitable factory that will then return to me a share of the profits", to just gambling "I think this stock price will change by the end of the day and I'm going to bet on it", and what are the positives and negatives of that?