Why eReader? First, it's not the only format I intend to use, only one of two or three.* I think eReader is the best format for Palm Treo overall, but I could change my mind. Also, it's pretty tied in with Palm itself, and a lot of my market uses Treos. FYI, that market is lawyers, which should explain why I'm not that focused on what the e-book community's preferences are-- most of my potential customers aren't savvy e-book users like this forum, but more likely just lawyers a little more tech-oriented than their peers. I've tested eReader books on lawyers in the past with positive results.
And I have to at least look into the possibility of DRM, although I am prejudiced against it, solely on pain in the butt aspects. But because I'm not giving my products away, I have to assume that there will be some theft, and it's only prudent to look into minimizing that theft.
*The other formats would be those I choose for reading on BlackBerry (looks like Mobipocket at this point) and iPhone (Stanza? eReader?).