what is the legitimate use case?

You do a whole bunch of research on a subject – hours, days, weeks, months, years maybe – and then find something that sparks a connection with something else that you half remember. Where was that thing in the 1000s of pages you read? That’s the problem (or at least one of the problems) it’s supposed to solve.

I’ve considered writing similar research tools for myself over the years (e.g. save a copy of the HTML and a screenshot of every webpage I visit automatically marked with a timestamp for future reference), but decided the storage cost and risk of accidentally embarrassing/compromising myself by recording something sensitive was too high compared to just taking notes in more traditional ways and saving things manually.