You can look at it two ways. XP is for Full line dealers to have a way to do budget add-ons to existing systems or have less expensive processor to work with other full line gear that they already have tempalates and modules for.
OR
you can see it as a way to encourage Prodigy Only dealers to sale an even MORE upgradeable path/product to their clients and hopefully move into full line dealers making them that much less likely to pick up another large automation company (C4/Savanat/ AMX).
I had a conversastion with my Crestron Rep (we are direct prodigy only) and he gave me pricing and eta on all the new PRODIGY gear and the "PMC3-XP" is a piece of PRODIGY gear and I have pricing for that as well. He didn't make it sound at all as if I wouldn't be able to use them if I wanted to.
That's just my personal expereince. The XP model's MSRP is more than double that of the standard Prodigy only PMC3.