There is no end to what if's.

What if Dropbox screws up? Data is gone!

What if your building catches fire? Those documents will burn with pleasure!

What if your hard-drive decides to get a heart-attack [crash]?

What if world ends?

Paper is so 90s thing. Even in offices, yes.

Don't be silly. It's reasonable to plan for disaster scenarios, especially in this case where it's something important, and the probability of disaster is unknown. Do you look both ways across the street, even if you have the walk sign?

We have copies on local machines too.