This isn't really meant to benefit you. This is meant to benefit our children. If the foundation survives longer than my own life, then I can put files that may be of value to my children and great-grandchildren. It would be up to them to value the preservation of their own digital history and cultural heritage to continue supporting this mission.
Both the founder of the Internet Archive and someone from the geaneology industry are among the board. I can see this idea being cooked up as, "hey, what if we were able to offer regular people their very own micro Internet Archive?" "What if we were able to pass on digital photos to be discovered by our descendants the way we have been able to discover photos from the late 1800s and 1900s?"
When viewed from that lens, about what happens to data after you die, $10 is a cheap gamble. This isn't really a promise made to me. This is a promise made to my kids. It may not be a promise that the foundation can keep, but I value contributing to my kid's heritage enough to risk $10.
I am still going to keep my Google Cloud and Dropbox, and whatever. But the 1 GB I have from this foundation is for a time capsule, stuff I really want to have a shot of passing it down. My kids won't care about my cat memes, or my passwords, or stupid videos. But they may want their baby pictures. They may want their grandpa's and grandma's dissertation.
When I die, my Google Cloud drive will shut down. But if things work out with Permanent.org, those files will continue to be there. I won't have to burden my kids directly with its upkeep. And perhaps, when they are older, they will come to value having access to it.
Maybe they have not sold their vision well enough. But I guess, they only need just enough people who gets it to kick this off. They are already 75% of the way there.