Me either. $9.99+$3.99 is better than paying $25.96, or even just using an Audible credit that gets you just the audiobook. It's just like a BOGOHO deal they entice you with.
And you see that on the actual book page these days, so it's not like you wouldn't know to begin with.
Works for those of us who do like Audiobooks, and books, but don't want to pay the Audible subscription prices.