Not quite. The certification of finances is used for visa purposes; it just documents that you have sufficient resources to afford your education in the US.
Colleges with need-based aid for international students will usually direct you towards the CSS Profile. It automatically computes a suggested contribution, based on the cost of living in each country, which makes it easy to use for colleges.
It used to be impossible for international students to complete the FAFSA form. You’d get auto-rejected as soon as you indicated that you’re not a US citizen or eligible non-citizen, before you specify which colleges to send the form to. Nobody except yourself and the government would have access to the incomplete application.
It’s possible that this has changed and international students can now share a completed FAFSA form with colleges. You still would NOT be eligible for institutional need-based aid or merit scholarships that are restricted to domestic students. However, it’s conceivable that some colleges have merit scholarships that are not explicitly restricted to domestic students but which do require a completed FAFSA on file for consideration. In that very specific circumstance, it may indeed be helpful to complete the form.