For something like this there’s ways to minimize how much you need to trust nodes such as regularly publishing hashes to 3rd parties like HN.
Not so useful if something was edited a few minutes after posting, but it makes it more difficult for a new administration to suddenly edit a bunch of old data.
What happens as websites disappear? With a blockchain in 2090 you can point to a website post in 2060 as support that your hashes on data posted in 2030 are still valid. That’s useful when preventing people from rewriting history is the goal.
There’s also a size advantage. You can keep a diff on the archive for each hash being posted instead of the full index for every time you post a hash.
Not so useful if something was edited a few minutes after posting, but it makes it more difficult for a new administration to suddenly edit a bunch of old data.