[greyface-]

> you always have to trust that they implement their white paper correctly

Actually, no - if they implement their whitepaper incorrectly, and I manage to keep my insecurely-encrypted vault blob private, I'm still safe. Bad implementation is only a risk if there is also a data breach. This is defense in depth. Your argument is based on an all-or-nothing model of trust, rather than one where trust can be contextual and partial.

Would you be comfortable uploading your vault somewhere 100% public, rather than behind authentication with iCloud/Dropbox/1P, since it's safely encrypted?