I wish someone would clone a service like this and make if self hosted. I am completely uncomfortable with sharing my email data with a third party company.
This sounds incredibly hard to achieve with email contents - nothing identifiable at all? Does it do things like strip names out of email bodies? It says they learn contacts under priority stuff (which seems sensible) - so they do that locally?
Looking at their other features - what are they sending messages to the cloud for?
No identifiable data leaves your device, and only anonymized info is utilized to build a "personal model" for a user.