While I have never been denied my reserved bed type, I have to agree with others that stating that something is guaranteed but has not backing for failure to fulfil is a terrible misuse of the English language.
In any case, I would refuse to pay the full booked room rate if the contracted type of room was not provided.
But other than that, it is good to hear that they are, at least at present, intending to make C&P permanent and, hopefully, enhance it. As others have stated, it would certainly be nice, not to mention logical, to be able to book C&P just as easily as booking a all-points award.