You don't need byzantine fault tolerance within an organization. You need at most regular signing. For an example of how this works in the real world, consider the French NF525 system where immutable transaction auditing is legally required. Unsurprisingly, it's not done with blockchain proof-of-waste.
>You don't need byzantine fault tolerance within an organization.
Maybe you haven't encountered a need for BFT in organizations that you've observed but it would be fallacious to say "...and ergo no organization would need BFT" (round-trip fallacy). I agree that an org doesn't need BFT if:
-Their hardware never fails
-Their hardware never goes offline
-Their permission structure never changes / No (permissioned hardware or employee) ever become unpermissioned at the human layer.
-Their hardware is in critical time sync with other system all the time.
-...
I have yet to see such a system but do see many people who don't realize their DS needs. That's fine, most people don't understand the delayed costs in not properly auditing unstable logs. Someone's got to work for bitcoin in the future.
e.g. https://support.mindbodyonline.com/s/article/Best-practices-...