Digitization as preservation?

All the cool kids are doing it. I read this snippet from the latest February issue of Information Today:

The LC digitized the 25,000 book in its $2 million Digitizing American Imprints at the LC program, funded by the Alfred P Sloan Foundation. The project, which preserves brittle books through digital scanning, digitized The Heroic Life of Abraham Lincoln: the Great Emancipator to reach the milestone.

Here is the link for the lengthier LC article: http://www.loc.gov/today/pr/2009/09-10.html