I'm very pleased to hear that the books sales are doing so well, it's encouraging to see that kind of response. Personally speaking I've bought more books for my reader in 3 months than I've bought songs from iTunes in 3 years so I can believe the claim.
Wireless integration isn't a huge deal for me either but I suppose it all comes down to what they want to do with it. It'd be nice to be able to "lend" an ebook wirelessly give the recipient the ability to read that book once before it's removed from their device. In much the same way as you'd lend a paperback.