This might work for gas, or speed, not so much for a tachometer. It's not just "red", it's where you are relative to red, or how deep in red, and how close to max you are. Its positive feedback when shifting gears (and a joy when you know your transmission)...
I can get in a car with a traditional tac and know a lot at a glance, A digital gauge conveys none of this information.
An analog gauge also gives you a very quick and intuitive sense of rate of change.
It's extremely quick, easy, and intuitive to see an analog tachometer climbing quickly and time a shift properly.
If there's anywhere where a precise value would matter, I would have to imagine it would be F1. They are certainly not sticking with analog gauges because "tradition" or "cost". And even if it were only better given an adjustment period or additional training, they would simply have made the switch and the drivers would have adapted.
Yet, while there are several variations, every team to my knowledge uses a series of lights which are even _less_ precise than the analog gauges most of us have in our car.
I can get in a car with a traditional tac and know a lot at a glance, A digital gauge conveys none of this information.