Last I saw you could download with a “hidden” URL (that a Greasemonkey script helpfully could provide), or you could use the PC app. Basically, it's not B&N's intent to allow you to download and sideload, but you can get around it for the time being. That's not acceptable to me, given that in the past you could download, and since they've signalled their intent (no sideloading of B&N content), why would I want to continue with them?

The few reasons I had for choosing B&N over Amazon have been removed, and after re-evaluating the two, I've decided Amazon does a better job of providing what I want.