"We do not use personal data from your Gmail account or other private apps and services to improve Bard."
https://policies.google.com/privacy
FTR: and for what it's worth the claim came from an ex employee who was fired from Google for leaking company seekrits and thinking it's,google's, (LLM)LaMDA was sentient
https://twitter.com/cajundiscordian/status/1638243303035670528
lil tip
you can use Flowcrypt browser extension, and android/iOS app, which will encrypt all email for you in Gmail for users
you can send all email encrypted or as normal within gmail on web you get to compose buttons one for normal gmail and one that will encrypt the email
you can also send encrypted email with passwords to folk not using flowcrypt at their end
#TipsAndTricks
Gmail Encryption in 60 seconds
https://flowcrypt.com/
https://github.com/FlowCrypt/flowcrypt-browser