The elephant in the room is "what to do about email", and a significant part of the issues are related to the "encrypt email" use case: part of the metadata leakage, no forward secrecy, ...
The closest advice to this in the article would be "use Signal" which has various issues of its own, unrelated to crypto: it has Signal Foundation as a SPOF and its ID mechanism is outright wonky, as phone numbers are IDs that are location bound, hard to manage multiple for a person, hard to manage multiple persons per ID, hard to roll over.
To me that seems to be a much bigger issue than "encrypting files for purposes that aren't {all regular purposes}".
The closest advice to this in the article would be "use Signal" which has various issues of its own, unrelated to crypto: it has Signal Foundation as a SPOF and its ID mechanism is outright wonky, as phone numbers are IDs that are location bound, hard to manage multiple for a person, hard to manage multiple persons per ID, hard to roll over.
To me that seems to be a much bigger issue than "encrypting files for purposes that aren't {all regular purposes}".