[
I]"You could burn its sand to glass."[/I] Palpatine is invoking Anakin's dislike of sand. I hope the writer meant to do that as a tongue-in-cheek wink at the reader.
As far as this topic goes, I've never really considered non-movie stories as canon. Whether it's comics, cartoons, or novels - the stories never seemed "official" to me, regardless of whether I've enjoyed them or not. But they're nice to have, especially when they deal with stuff that bridges gaps left unaddressed by the movies.
The problem is that some of the non-movie stuff is so excessive that it can get contradictory. These stories can be more enjoyable for me sometimes when they don't "count." Helps keep actual canon less messy.