I'm a fan of this approach to users owning their data: it enables things that are interesting and valuable for the user, rather than making it something that necessarily requires an audience.
I hadn't previously considered incorporating notes into a personal archive as I often see them as being of a fundamentally different class to journaling, but I'm starting to reconsider my biases in that regard.
However, I love flipping through old notebooks. They're a personal diary made of schematics, sketches, lists and recipes.
I'm now a bit more conscious about dating each page, because I combine those with other data to form a personal timeline [0].
None of this is about productivity. It's closer to an artistic hobby like calligraphy.
[0] https://nicolasbouliane.com/projects/timeline