Not that I think it's an invalid argument, but almost all of our outages have been either a database issue or (far more often) CloudFlare's inability to reach us (the origin) across the internet. Deploying code rapidly very, very rarely causes an issue.
To us, the speed of deployment and overhead savings we get 24/7 is also absolutely worth those very rare issues.
Thats pretty amazing actually! While I certainly have seen a fair amount of code that passes (even good) automated testing but fails on validation, it feels somewhat strange but starts to make sense after a bit to value heavy monitoring more.
Good modularization of code I think makes this more possible - the point of a big test suite is to catch unintended consequences of a change, and the less coupling the less likely this is to happen. Stuff like routers, session object and other stateful/lower level logic I'd imagine is more tricky to change without a test suite
To us, the speed of deployment and overhead savings we get 24/7 is also absolutely worth those very rare issues.