But that's just an hash chain, it has existed for longer than the blockchain. For example, all digital invoices in my country are hash-chained, to prevent the merchant from swapping one for another, and this standard was published before Bitcoin.
I don't disagree with anything you said. Even generously most of the "blockchain" hype is an excuse for cryptography that has already existed without application for some time.
It's not that special, each invoice gets assigned as hash of (invoice number + total amount + date of emission + hash of previous invoice). Besides having to send that XML file to the IRS each month with all the issued invoices, the hash also gets printed on the invoice given to the client (paper or PDF), so it gets tricky to change the past without getting caught.
