I like that more people are thinking solving some of the problems of digital inheritance we face. These are problems that are so important now that so much of our lives are digital and tapping into ones actual social circle seems the best way to do this.
Also, kudos for packaging it as a static web app. That's the one platform I'm willing to bet will still function in 10 years.
As someone who still plays Windows games from 30 years ago and Flash games from ~20 years ago, I'd not be so pessimistic about other platforms, at least when there is no negative sentiment towards it and a good track record of stability. Not to say that the web is not among the best choices