I'm pretty sure any industry that handles documents etc. that would require a non-forgeable timestamp would not want (or are allowed due to regulation) to upload a billion dollar contract, legal document or patent to a website. No offence.

They would want an in-house, closed system with (of course) blockchain communication for the verification part. Or maybe a tool that creates a "Magic" executable that contains the a) file and b) a "Check" button to do the blockchain verification.