> “don’t help managers”
Managers are people too, despite of what Dilbert will have you believe. They need help, support, and tools.
It's true that many tools and frameworks are sold as magic pills that solve all the problems. Metrics are one of those tools that are often misrepresented. I think that many of the tools are helpful, if used skillfully.
You can't manage what you can't see. You see your team through your direct interactions with them. You see what they do through the artifacts that they produce. You learn about them from others - hear-say, praise, complaints, and gossip. You also get another perspective through various metrics. You need to combine multiple ways of seeing a team to have a more-complete picture. Take any of them away, and you're a little more blind.
I remember when I first transitioned into the manager role. There was so much that I needed to learn. Some of the tools gave me insight into what is happening on the team that I really don't get to observe directly. However, none of the tools did my job for me. I learned by reading, using new tools, and experimenting. Over time I honed my ability to be able to understand what my team is doing well, and where it needs help. If someone took away ALL the metrics-based tools, I would have fewer ways of evaluating my team.
Managers need as much help as anyone else to do their job. This also involved introducing new tools, and teaching managers how to use them. In a large part, that is their manager's job. Sometimes they call me to help.