I'll be completely frank... it seems like penny-pinching to me.
It's like the rear air vents that reviewers have been on about. Save a smidgeon here and there to the detriment of the vehicle. I am not too concerned about that but I use the digital speedo all the time; I do not look at the dials at all. I actually think dials are a bit of an anachronism, just like the silly massive handbrakes.
That said, it's not out of the running completely... because of 2 things... 1 is that I'm going to have a look at the Q3 later today but that'll come in over £35,000 and that's not something you just forget about, 2 is that I'm going to have a look and see whether any kind of digital speedo. can be purchased and installed in cars to give accurate readouts... if it was small and unobtrusive and battery powered, then maybe I could stick it somewhere? I would be happy with that.
The road you mention, I'm not aware of - but there are roads like that around here as well, and the M1 has had sections of 50mph average speed checks for years, and will do for years I bet.
Please tell me more about the sat. nav. view map thing that gives you an actual digital speed??? Are you saying there is a screen somewhere in the car where a digital speed readout is present???