If you're happy with your agent's performance using surface level o11y to track down issues then that's fine. This is what pretty much the entire industry is doing and it does usually work! QA focuses on root causes because it can look through the app's entire execution and provide evidence so your agent doesn't need to guess when figuring out what the fix is. That guesswork is what we're trying to eliminate, for when the surface level stuff doesn't clearly point at the problem.