Even ignoring the historical value, it's easier to hack into a server and edit a file than it is to forge a legal document and break into an archive. Suddenly, you're the legitimate heir to a castle.

Should we then destroy all legal documents, for example The Magna Carta?

Museums aren't just a store of "art", museums are a way to preserve our heritage, preferably in its original form.

That makes the originals even more important.

Not art, historical artifacts. There’s tons of info that a picture wouldn’t capture. Type of paper and ink used, isotopic analysis, etc. Who knows what questions future historians or archeologists will want to ask?