Cinema is the most important window in which to view our culture. Film preservation is essential. To alter what has already been done is not only a poor artistic decision; it is also a defacing and elimination of a cultural milestone. (*cough* Mr. Lucas *cough*)
While film preservation is a must, I believe film prop preservation is also essential. To be able to see what was used in a film says a lot about the craft. To hold a prop from something that has been a pop culture mainstay to millions would be quite an exhilarating experience.
Case in point: Giger’s “Alien” head from the 1979 film. This is the actual Carlo Rambaldi mechanical prop.
Nicely preserved at Giger’s estate in Zurich. Notice the human skull in which the entire head is formed around.
Now, what if this was CGI instead? What would we have to display? At the very most maybe a small maquette or model that they would have used to scan in into the computer, but nothing that would have actually been seen on camera. This “Alien” head is tangible. We see the wires. We see the remnants of prophylactics on the jaws. We see the tool that was used for a very familiar cultural image… and it is awesome.
CGI doesn’t offer this.