I used to think this was about the act of writing in itself - that doing it by hand forced me to be more conscious of the information - but writing with e.g. an Apple Pencil on an iPad is just as useless as typing.
I'd really like to figure this out because I love the idea of searchable notes that are available anywhere, any time, and aren't dependent on a dead tree for their longevity, but I haven't found the solution yet. I have a theory that it might be related to the fundamental experience (friction, texture) of a pen and paper, so I'm considering a reMarkable[1] but I'm wary of obsolescence.