FTA: "We don’t use any information from your Gmail messages to serve you ads, and that includes the email receipts and confirmations shown on the Purchase page"

Other companies like unroll.me, however, were absolutely data mining your receipts and then selling the results.

He specifically said Google Workspace which is the non-free version of the Google suite.

Two ways I can see as an outsider: 1. Google Drive/One/whatever subscriptions to pay for more storage if you want to keep your old emails/files in their cloud. 2. Keeping people signed into their Google account for email could make them easier to track as they're also identified/signed in elsewhere on the web.

Gmail runs ads in the consumer version, but the ads are powered by the search and activity elsewhere.

But also workspace more broadly wants people to use Gmail in their personal lives so they want to use it at work, which then is a paid business.