Stilt provides financial services for immigrants by underwriting loans with cash-flow data, allowing them to access the US financial system. The company initially attempted to build their own functionality but realized that partnering with a connectivity provider like Plaid would be faster, easier, and more secure. By leveraging this partnership, Stilt can access an applicant's financial information and gain a more accurate representation of their ability to repay. This approach enables Stilt to bring more people into the US financial system, providing them with much-needed access to credit and other financial services.