What is worth keeping for a million years?
Very especially since we're not likely to exist around that time...

What we should be concerned about is how long our film will keep for in ideal conditions as opposed to the ambitions of digital; I doubt very, very much that any digital photograph produced today will be readable in 20 to 30 years. Whether we will still have film then is a matter of conjecture. Whatever we have in a million years will not concern me.