[jrumbut]

Given that there isn't one number (or five numbers or five thousand numbers) that can tell you if your engineering team is good or bad, there is no easy mapping between high and low velocity and good and bad, and velocity can't really be compared between teams or even the same team on different projects, it does have uses.

Particularly when a team has multiple projects, looking at each project's velocity helps you see if you're smoothly building out new features, getting bogged down, distracted by bugs in an old project, consistently underestimating the effort required for all things, etc.

It's a terrible target, not good for evaluation, but a handy metric for a PM to quietly check and use to make sure things are proceeding smoothly. The PM should probably know by other means but no one is perfect.