The fastest GT-Rs are running a tall 60+ M&H racemaster anyways.
Let's be honest here, NO ONE is going to drive in the snow, rain or elements with a 1200hp-1500hp car, (as much as someone would brag they could). With that much power it's also virtually useless on a road course.
So, why have street tires? The only car I know of that's run very respectable times on low profile street tires is the TTG. It ain't gonna drive a whole different if it was a drag radial either. How significant is it really in a 1300hp car...:shrug:
These are also owners with an absolute asinine amount of money invested in their cars, do they really need the 'drivability' of street tires in a race car that makes that much power? ****, they can afford a s65 or rolls Royce to DD.
If it were a Mustang owner or someone who really has to daily drive their 600-700hp car everywhere I could see the significance.
You have a point with not needing to drive 1200hp cars everyday, but a lot of owners WANT to drive their 1200hp cars everyday. If you are able to perform with a 100% no DR road tire then why wouldn't you? With the MoTec progressive boost a ton of the Lambo guys have already proven that the R888 can do anything they throw at it including hold 1500whp. If this is the case then I would definitely like the added performance of being able to brake, turn, and take adverse road and weather conditions should you encounter them.