I wouldn't agree to that really as knowing your speed down a straight is pretty vital if you ask me, if you're not doing what you think you should be doing you'll know that the last exit wasn't as fast as it could be. A few M/Kph down a straight might not seem to matter when you're fighting for 2/3 seconds but when you get down to tenths and such, every extra bit of speed you carry on the straights makes a world of difference.
+1 to the idea if its an option but I still rely on the speedo when I'm racing in every car I drive, so I don't want it to be forced or have a massive blanker plate where the speedo should be (I use analogue) so no Digi stuff!