I think a bad metric is very much worse than nothing. It sucks away time to record, debate, report, and discuss. It encourages bad decision making. If you throw up a number people will give it weight, even if it's stupid. Multiplying 6 gut checks and trying to make a decision about engineering direction is like tracking someone's mood by the metric of whether they ate an odd or even number of calories yesterday. There's theoretically a signal under all that noise, but the direct gut-check or any number of qualitative clues are so much better than the distracting number.