Is there an instrument like the SG etc. which has a bar type display for instant MPG ? Something like this one which is the same as the one I had on holiday earlier this year.
A study I was reading about (for older cars in a mag so not online) recalls research designers did into digital instruments of the kind popular in the 80s onwards and still used in some cars like the Prius. They noted that although we can read numbers quickly, a trend upwards or downwards is more quickly interpreted by a graph or gauge.
This is the same reason I spent money on a rev counter for my Aygo instead of using the RPM gauge on the SG.