The idea is not to make a final decision whether to use redux for a SaaS project or not. It’s just more about when you get started and have to validate your business idea, you don’t want redux to slow you down without giving you any benefit (yet). Once you get to product-market-fit with your idea and you know you have to really build the full thing now, then it might be time to start using the flux pattern. However, even in that case you might still put it off until you really feel the problems that redux promises to solve.
Compare it to setting up a small coconut selling business at a beach: You wouldn’t hire an architect, lay proper plumbing and electricity — you would just set up a table and start selling! Once you see your business growing, you will reach a point when you know you have to install plumbing and hire an architect for a bigger building.