There are different ways to monitor a system to ensure its performance, stability, reliability and resilience. Along with the "usual suspects", we also use end to end tests for this purpose.

Recently, I read a Tweet by Maaret Pyhäjärvi concerning the value of test automation. She claimed that "Lack of test automation moves known knowns to unknown knowns."

I strongly agree because if you don't have automation in place to "remind" you of known issues that might come up again, you will forget about them. In my view, test reporting plays a strong role in this as well.