Agreed.

As an example, I buy sheet music PDFs from online stores. The stores often show the first part of a PDF and then you pay and get access to download the PDF.

It would be easy to imagine then replacing their system with this.

As a customer, I see no real difference. If I paid the store and didn't get the sheet music, of probably be stuck in credit card chargeback hell anyway.

As the store, there are probably some downsides. E.g. their own system can probably give me a unique link. That link may expire after I use it. With this system, there's nothing preventing me from tweeting the link if I wanted to.