I love most of the sentiments here for journalling but strong question if someone will be looking through is "graph" in Roam Research (or any digital tool actually Roam is just what he cites and uses).
Text on paper is so much more accessible. You find notebooks in boxes as you unpack from a realtive dying, you don't find their Roam graph in a box. It's lost to the world unless you take extra steps and those that come after you also are nerds and know to look for those extra things. This is why I journal on paper alongside much of my task management in a Bullet Journal style notebook.
I even get his idea of a fire taking out your notebooks, still scanning PDF's seems like a better option to me to backup your notebook.