It's a good point.

After driving my Prius for only a short time, I found myself using the instrumentation to help me drive more fuel efficiently. So, no, I don't expect my car to simply "do it all for me".

And I have also thought that it would be beneficial to have a "real-time fuel use" gauge in ALL cars. I can't help but think that if people could just see a visual display of how their use of the "loud pedal" influences their gas mileage, some of them just might drive more fuel efficiently.