Ok, fair point, they prove that content existed at some point in time, which is useful sometimes. But I don't want people to over-rely on that as "good enough",

Ok, fair point, they prove that content existed at some point in time, which is useful sometimes. But I don't want people to over-rely on that as "good enough", we can do much better, it's too low a bar for a whole ecosystem of archiving to rely on when we now have a viable solution to fix it (TLSNotary or others).