Actually, due to pseudo-immutability, scribblings on the dead trees have better durability properties than many digital things.

A durable storage may be less prone to use data due to say, a fire or a flood, but it's way easier to lose data if it's just overwritten. Overwrite a file in-place and it's pretty much gone (good thing most editors don't, but create a temporary file then rename it, so old data still can be scrubbed from HDD). That had happened to my files a few times, but never had such experiences with paper.

Not to say commodity-grade paper may easily outlive commodity-grade HDDs, magnetic tapes or CD-R's. I still have my notes from university, but all the CD-R's I've burned around the same time are unreadable, and I've replaced dying HDDs quite a few times over past years. And paper is probably easier to recycle (although not sure about this).