Gennie Gebhart and Cory Doctorow, for the EFF:

While many of its features sound promising, what “Confidential Mode” provides isn’t confidentiality. At best, the new mode might create expectations that it fails to meet around security and privacy in Gmail. We fear that Confidential Mode will make it less likely for users to find and use other, more secure communication alternatives. And at worst, Confidential Mode will push users further into Google’s own walled garden while giving them what we believe are misleading assurances of privacy and security […]

Ultimately, for the reasons we outlined above, in EFF’s opinion calling this new Gmail mode “confidential” is misleading. There is nothing confidential about unencrypted email in general and about Gmail’s new “Confidential Mode” in particular. While the new mode might make sense in narrow enterprise or company settings, it lacks the privacy guarantees and features to be considered a reliable secure communications option for most users.

The one thing I trust Google with is their uncanny ability to try to create an illusion of privacy and security, while in reality doing the exact opposite.