I'd argue as your visitors scale, so should the ability to trace individual requests, and as your user-level support team scales, so do the tools you use to support them.

Another nice benefit is that building out a quick internal tool can be a great afternoon hack to clear your mind. It doesn't have to be good, just something to remove some pain.

We're tagging pretty much every request & correlating it with a user, and are able to pull logs pretty quickly. It's not hands-off, but we've built tooling to make it pretty straightforward to dig whats up.