The idea is a little overkill for non-geeks/ non-interweb users like my parents, for example. For someone like me, the idea of having every ounce of my digital being downloaded into my tombstone is a very exciting idea.
We dump a lot of ourselves into the internet. Be it through images, words, or other expressions - all of your online personality can be left in one place, in a format that family can pull up at their leisure. A child can learn more about her ancestors. She can flip through beautiful photographs family long ago. Read Grandpa's blog post on the day he first met his granddaughter.
It may sound a bit like unhealthy denial, but I see it as more of a remembrance/record keeping artifact. This is who I was. This is what I did. Come and learn about me. You know, that kind of thing.