Simple Question

I'm a small-business owner — an upscale supermarket in the Santa Ynez Valley — and I have a question no financial guru has cleared up for me.

Why is the stock market considered an investment? When I spent $50,000 on a sushi bar in my store, I was banking on a return from added value — turning fish and rice into something customers would pay more for. In what way is buying a stock that doesn't even pay a dividend the same kind of thing? Except for IPOs or equity-funded expansion, companies don't directly benefit from the movement of their share price. From a real perspective, I just don't get it.