Interesting, I suppose. But they'd probably sell a lot more if $9.99 were the everyday price and their "special deal" actually were, at least, a "deal".
Looks like it is $9.99
in the Kindle store, as well. Since it appears that Amazon sets the price there (no note that it is set by the publisher) and it isn't on the limited time offers page, it appears that, in fact, $9.99
is the normal, every day price, making this even less interesting.