Plenty of cars have had something similar in concept for many years now, be it an economy guage, a gearchange indicator, gearchange lights built into the steering wheel, etc. On our Honda Jazz, the lighting surrounding the rev counter and speedometer changes coulour depending on whether you are driving efficiently or otherwise. I think the first time i saw something like this on a car was in a 1980's BMW (3 series i think), it was just a simple guage to show if you were driving efficiently or not, but it did the job if you were interested.

I've seen the economy gauges ect bot my cars have them as do most now days and one has the up down arrows. Maybe they think this will be more informative than the traffic light system used on heavy commercial vehicles.

One of my last CPC courses was about fuel economy and green band driving. It was all about keeping it in the green band as much as possible which in practice is a good idea and will save fuel but working in one of the hillest parts of london doesn't get you high marks on the tracker system .

I've a pretty good idea of where peak torque is/was in any car I've owned and it's not where the 'nag light' thinks I should change up - 3k+ revs not <2k.

Tachometer helps but for years in Mini (the sort Issigonis designed) and other cars I judged it by ear.