It would help! It would establish that an archive was made no later than the date it was recorded on a blockchain (assuming the archiver isn’t also the one the made the original content in which case they can upload it after making the “archive”). You would still need to prove the trustworthiness of the archived data and at the moment the only thing we have for that is just trusting the archiver.

You could do something like have multiple archivers archive the same site in s stripped down for like plain text (so that differences caused by time or day, ads, etc don’t change the hash) and that way you can say that X amount of archivers agree that the site looked like that at that time.