Earlier quoted context omitted.
This is spot on. A KPI is not a number, but rather a number, a direction, and a target. Also, gauges are almost always a terrible visual indicator. Even car dashboards are starting to understand this. Fuel gauges are good, speedometers are not.
Why are speedometers not good? Speed is analog, seems appropriate to display it in analog. And you can tell at a glance if speed is increasing or decreasing by the direction the dial/indicator is moving.
The gas gauge however has a permanent meaning. Empty is bad. The Tachometer is also useful if you are driving a manual since you want to keep from redlining and keep from stalling.
On almost every business dashboard I have seen, gauges are more like speedometers.
People love to put revenue in a gauge. More is better and they usually have a goal that they want to hit. But what happens if they max out the gauge? Do they stop sales? Or do they adjust the gauge to go higher (thus making it even more meaningless and difficult to read).