Having driven through Nevada (not just in Vegas) many times I have to say that you certainly wish the speed limit was much higher. Once you get outside of a city so much of it's just desolate, barren land for 100s of miles in every direction. Much of it is very boring often with very few other cars on the road. I have no statistics but I'll bet that a large percentage of accidents that take place in the rural areas of Nevada (99% of it is rural) are related to falling asleep or driver distraction while trying to find something to do to keep them awake.
But yeah, this law would likely increase the accidents significantly just out of driver inexperience at those speeds. Also most inexpensive tires aren't rated for over 85 mph for long distance driving, which is all you do in Nevada.