Financing is important for small businesses in a variety of ways. Needing quick money often has connotations of having poor cash flow and not being able to meet your short-term liabilities. This is far from the only reason for needing business financing though.
Financing is often a solution for growth projects when businesses owners do not want to dilute equity any further. The conventional way to grow is to sell a portion of the company to an investor, in which you can raise perhaps hundreds of thousands without adding to your debt.