As sensors get denser with pro-spec cameras, there seems to be some lethargy in adopting a higher and faster storage medium.
UHS-I is already making its rounds in the market at up to 95MB/s write speeds. These are compatible with SDHC class products but the newer UHS-II is not backward compatible due to the different pins as seen in the picture.
I would hazard a guess that UHS-II is just too pricey an option for now. UHS-1 is probably a better bet with your spiffy new DSLR. It cost roughly $129 for a 95MB/s write speed capable 64GB whereas a Class 10 30MB/s SDHC with with the same capacity will set you back about half the cost at $40 bucks a pop.
For pro spec video use, you need a minimum of 128GB with UHS-1 with a ballpark price of $120.
128GB CF cards? It can cost up to $400 a pop. Let the maths do the work and you'll soon realize that CF cards are going phased out within 3 years.