@HunterNP note that encryption isn’t the only thing to look for; the real key is do the app makers retain any access to the account. Might be w best of intentions: routine IT service, password rescue, and such, but the two questions are: A) what happens if they get a subpoena/warrant and B) what happens if they go bankrupt, invalidating all contractual promises and transferring control to a trustee who dissects them to a pile of digital assets for the highest bidder.
Use paper.
@AmberWavesofFlame Thank you! This is so so helpful. Despite knowing zero about tech/legal matters I’m frequently asked about such things by patients who are understandably concerned. While I always give the caveat that I can’t give legal advice, it is good to know that for the multitude of reasons you listed playing it safe and using paper is best.