Well, let's look further into the past. Petite Cossette was released on DVD (since it's an OVA
), but had a standalone OST. Or was it simply because OVAs are normally not bundled with their OSTs at once?
Sony's logic beats me. Bundling was a good choice for KnK, seeing as the OSTs had varying lengths and nameless tracks - coupled with the unusual character of the music, it could probably have been tough to sell separately. But then, with Madoka, it looked more like a safety pillow ensuring some surplus for the BDs back when no one was really certain how Shaft's first original work (and a dark magical girl series at that) would perform. Too bad; as someone at AS said, "they could have made Oricon history with this". It's the same cauiousness backlash that supposedly left us with Oriko crammed into 2 volumes instead of a proper (at least, Kazumi-sized) serialization.
But what's the issue now? They're adapting a popular novel from a popular franchise, employing a popular staff. Which would seem like the high time to lay out every card without fearing losses. The BDs should do well on their own, while a separate OST may be purchased even by the people ho didn't like the show. But no, we want to make them ALL buy stuff at once and double price, don't we? So if they have an understandable excuse, they'd better voice it soon... Or say that the whole rumour was a troll joke.
TL;DR I like how Sony gives us a lot of BGMs normally left out. But I'm not sure if I like how Sony seems to be turning a trafitional industry practice into a BD bonus feature. It may actually backlash on them and lower the sales, stripping them of potential profit from BOTH the show and its OST.
By the way, remind me to look up Oreimo and Angel Beats OSTs. I wonder if this policy extends to other Aniplex productions or is somehow exclusive to Yuki's OSTs.
(understatement tag again). I'll opt to hope for January.
and with the BD box too ? 
sony really wants to make the fans poorer.
For her latest OST release with Flying Dog, Pandora Hearts, they happily put her name on the cover in big letters, and I suspect it was done to attract attention. 
The percussion music kinda reminded me of the Sayaka x Kyouko battle. 