Examples include government agencies who used made up in-house encryption schemes to get their data sharing plan past their legal privacy and security gates and then there was a secret key a small cadre had who could unscramble it after it was distributed in the sector, researchers rejecting synthesized data for uncontrolled test environments because "it was too hard," when really they just wanted the data sets outside the legal controls on it, rejecting differential privacy queries because they didn't want to come up with or specify their queries first based on metadata and again just wanted the data, rejecting identifying the individuals with access to millions of peoples health information data because as institutions they felt entitled to it, banks and payment firms rejecting zero knowledge proofs of user attributes because it violated KYC, and these are just a few.
There has been a concerted effort to squeeze the data toothpaste out of the tube when it comes to health information and other types, and so I am ambivalent about FHE use cases because its primary use case is side stepping rules that protect the privacy of data subjects.
The question I would have is, if data synthesis, legal risk-based de-identification, differential privacy, and cryptographic tokenization protocols were insufficient, what technical improvement in actual accountability does FHE offer to data subjects, and given the size of the data sets this facilitates, what are the consequences of its failure modes?
Given the entire history of cryptography is defined by one party convincing their targets that a given scheme provides them security, the way that FHE scales to giving data collectors impunity "because it's encrypted!" seems like it is vulnerable to every criticism leveled at blockchains, where just because it's encrypted doesn't mean it isn't laundering.