Interestingly, some do. The thought of making some money by buying a small amount of some high-growth stocks, with fractional investment being a thing for several years, energizes many small-time users of Robinhood and similar services. It's still a better gamble than buying lottery tickets, which many poor folks do a lot, sadly.
Poor people are people like us (or sometimes are us), some are quite prudent and would love to make an investment that pays, even if it's small.
Which of course, they do.