I teach a graduate class in Creating, Managing and Preserving Digital Assets at Syracuse University and last year I found that some students did consider digitization a form of preservation. Typically I hear people argue that if an item is used less due to digitization, then it is being preserved. Of course, using an item less does help to preserve it, but an archivist would want the item to go through some conservation efforts, etc., in order to ensure that it is preserved. However, these students were not thinking of that, but instead were looking at the preservation of the content through digitization and not of the item itself. Preserving the content is indeed important. If we are relying on digitization to do that, then those digital files must be properly preserved for the future. These students didn't consider that the item itself might "tell" a story. Researchers might, for example, be interested in the words written in a book as well as the book's binding, paper, ink used, etc. Those things cannot be captured by a digital file.
From working with those students a year ago I have learned to talk more in depth about why preserving the original item is important. I do acknowledge the role of preserving the content, but hope that we don't lose sight of the value of the original item.
Learning how others think about preservation was a very valuable lesson.