For me it boils down to trust in the service provider (in this case Proton) and the risk of anyone accessing your information. While your proposed solution is elegant and super accessible, it’s not without risk.
Relevant risks could include your device being screen- or keylogged or even the TSA randomly selecting you and forcing you to open up your phone under the implied threat of a free vacation to El Salvador.
For super sensitive data that can be memorised, I recommend memorisation. You can keep a backup hard copy in a safe place, even if that’s not immediately accessible. This should also be accessible for your relatives in case of death. Such a safe place can be a safety deposit box or even just a trusty old envelope stashed away behind a specific drawer.
For sensitive but not super sensitive data that you need on the go I recommend using an encrypted hard copy, which you can keep in your purse or wallet. Use any publicly available (long enough) document as your cypher, such as the Magna Charta or the Declaration of Independence (although I recommend more obscure texts, obviously). You can even use the cypher method for digital sensitive data if you prefer that. As long as you don’t tell anyone about your cypher you should be fine. It can still be brute forced, but should be really difficult if you use the right cypher.
For me it boils down to trust in the service provider (in this case Proton) and the risk of anyone accessing your information. While your proposed solution is elegant and super accessible, it’s not without risk.
Relevant risks could include your device being screen- or keylogged or even the TSA randomly selecting you and forcing you to open up your phone under the implied threat of a free vacation to El Salvador.
For super sensitive data that can be memorised, I recommend memorisation. You can keep a backup hard copy in a safe place, even if that’s not immediately accessible. This should also be accessible for your relatives in case of death. Such a safe place can be a safety deposit box or even just a trusty old envelope stashed away behind a specific drawer.
For sensitive but not super sensitive data that you need on the go I recommend using an encrypted hard copy, which you can keep in your purse or wallet. Use any publicly available (long enough) document as your cypher, such as the Magna Charta or the Declaration of Independence (although I recommend more obscure texts, obviously). You can even use the cypher method for digital sensitive data if you prefer that. As long as you don’t tell anyone about your cypher you should be fine. It can still be brute forced, but should be really difficult if you use the right cypher.