As the saga of Unroll.me[0] tells us, services like these will inevitably turn on their customers when they need to squeeze out more money than what they're charging you. Unroll.me may have been free, but as we've seen with modern SaaS, there will always be an upsell around the corner:

https://www.theverge.com/2019/12/17/21027159/unroll-me-email...