That's only true for very specific threat models. For most people, the limit in entropy for your passwords implied by keeping them all in your head makes them more vulnerable than writing them down in a place with imperfect security.
I like it because there isn't any third party or service for me to trust, but I can still have unique complex passwords for each purpose. It feels pretty much the same as having them all in my head.
It just posts an encrypted json blob to a CGI script that waits for another connection with the same ID. The script then connects those two connections so that anything one sends the other receives using a FIFO, so no disk involved and they can stream as much as they want to each other.
Poorly at present, but it runs as a website on anything with a recent browser: https://kybernetikos.github.io/sinkless/ and you can copy and paste, or there is a node script that will generate the same passwords.
I'd like to make the UI work better in general, but in particular on mobile devices. But then I have many projects I'd like to make time for, and this one is probably usable enough for me for now.
