They don't have to do that because Google doesn't sell any data
https://goo.gl/XNykgg (Disclaimer: Referral)
But basically, Google for Work is like normal Google services (Gmail, Google Drive, Hangouts, etc), except without advertisements and more restrictions on what they do with your data:
https://support.google.com/work/answer/6056650?hl=en (Privacy policy for Google for Work)
There are of course other benefits and extra controls/features as well, but it at least covers your main point.
https://goo.gl/XNykgg (Disclaimer: Referral)
But basically, Google for Work is like normal Google services (Gmail, Google Drive, Hangouts, etc), except without advertisements and more restrictions on what they do with your data:
https://support.google.com/work/answer/6056650?hl=en (Privacy policy for Google for Work)
There are of course other benefits and extra controls/features as well, but it at least covers your main point.