They have also bundled the spelling checker into the 'smart features' so turning off AI removes a core feature that has been there for 20 years. This is a 'dark pattern' of deliberately dysfunctional design aimed at coercing the user to go against their own interests and to invalidate their choices.

Many people have noted that the Primary / Social / Forums / Updates tabs are missing when you do this 👀. You can recreate these manually using the "Multiple Inbox" setup in settings. Basically, tell your inbox to include emails tagged "inbox" and exclude the social / forums / updates.