Shareholders generally like businesses to use their money on things only that business can do.
If the best thing the business can think to do with the money is put it in the stock market or a low-interest cash account, which anyone could do, investors usually demand that the money is returned to them (via dividends or share buybacks) so they can choose what happens to it.
If the best thing the business can think to do with the money is put it in the stock market or a low-interest cash account, which anyone could do, investors usually demand that the money is returned to them (via dividends or share buybacks) so they can choose what happens to it.