An interesting use case: I run a global sales organization and I started using blockchain based notary services on and off to timestamp original documents (after some mysteriously showed up at competitors), notarize email receipts and even notarize documents like passport and drivers license. Some law firms in the US now accept it. I use a blockchain notary service called stampery.com. There are many. Once time I notarized my rental car fuel gauge because the rental car company usually argues about that. I routinely notarize important brainstorming notes from whiteboards and critical text messages that the email notary does not get.For years I used an email certification service for such timestamping. This is much easier.
Commercially they are used to timestamp invoices / goods receipts, contracts, checks, bill of lading, transportation CRM, Airbill, Proof of Insurance etc. It is impractical and not scalable to notarize business documents and emails using traditional notary services.