That seams to be one of the best use cases for this, provided you can run it without giving Microsoft a lot of data directly. Else this is a no-no for enterprises imo.
But unlike Microsoft's other services, AI needs data to train on - are they going to be content just sourcing this from the internet at large or have we finally hit an inflection point where they try to get business and enterprise customers to give access in exchange for these features? That's a big no-no to anyone in a field that deals with sensitive information, and in most all cases an equally big no-no to anyone in a company that wants to keep things confidential.
You don't have language in your agreement that Microsoft cannot use your data to provide or improve service. You have language that says _support personnel_ cannot access your data without approval.
Microsoft already indexes your mailbox, OneDrive, etc.
Viva Topics has been around for ~2 years which mines content across various services.
As far as 'no more access than', OAuth apps can have full control over your tenant and all data.