I would love that to be the case since I'm 5E throughout the house and not RG59. But Scott says "No," it must be coax.
ATT Uverse out here is promoting their wireless receiver (comparable to Joey). Not needing coax or CAT5 makes it attractive to me. Of course, I live out in the sticks so its not currently an option for me, but it is an attractive feature, just like the built in homeplug on the ViP boxes.
Such is the way it goes, though. Can't please everybody.