Honestly, that sounds pretty fantastic. I've been using 3rd party tools/extensions to do this sort of thing in corporate and government environments for years, but having the attestation go all the way down to the hardware level is a big value-add, especially with so much ransomware/spyware/extortion/espionage going on these days.
Can someone please explain to me how the author might see this level of security as a bad thing?
At a past job, we used Entrust [0] and I'm aware of Virtru [1] as well.
Edit: I forgot about Sharepoint, which also sort-of fills the ACL document-sharing niche. (though I'm less certain about whether it uses encryption to enforce its access policies)