Meh
IMO it's more an issue of formatting and adding links than anything else. LP and other guidebooks use layouts that are optimized for paper, and probably didn't put huge efforts yet into their ebooks. Once they get the hang of it, and certain methods get more standardized, ebooks will be fine for travel.
It's also entirely plausible that a media-rich ebook will, in a few years, produce a vastly superior experience to paper. Imagine using a light-weight 7" tablet, full color, with zoomable maps and a GPS-based indicator of where you are in that map; an audio walking guide to a museum; perhaps even user-updatable information, indicating that the "backpacker's favorite cafe" is now closed, weighing a fraction of that massive Frommer's Guide to Europe.