1: Sales would not be judged like other albums, so the media can't say she's not selling like she used to... christmas albums are not usually judged by sales
2: Since whitney is still loved most for her gift (her voice) and has been called by so many as the voice of this generation that many people would be inclined to pick up the album, people who are no longer fans, and people who like her voice but they don't buy her albums (there are a lot of those), no matter what they've been hearing lately, its a christmas album by a legend who's never released one, I think many different kind of people will buy it.
3: it elimenates the pressuer that would normally be in a new album of what musical direction whitney should take and especially at this time when her image is fragile, so with a christmas album they don't have to worry about that and it gives them time. That also might explain the absence of new original songs except the title track.
4: I think they know it'll really please the fans, who at this point have been patient towards whitney through a lot....
And many more points. What I'm trying to say is that Arista did not have a christmas album planned when they signed her 100 million deal so its not like they were planning this ahead of time, maybe the album itself, but not this year in specific. So I think this album came about as a reaction to all thats been going on and they felt this was the best thing for her to do at this time.
The only thing that throws me off is the album cover, the fact that its not new made me rethink this whole thing but maybe they just don't really have the budget right now. All I'm saying is this is a strong possiblity and if this is how they feel then they need to back it up with good promotion, they can have so many headlines going on, finally a christmas album by the voice, or after 20 years as the defining voice of our generation whitney delivers a christmas album .... you guys put your inputs