What an export is
A data export is a copy of selected information from an account at a point in time. Google Takeout, for example, can package mail, photos, calendar data and other products into one or more archives. It is useful for portability and records, but a one-time export will not keep itself current after your account changes.
An important distinction
Exporting photos before closing an account does not prove that every recent change made it into the download. Google says changes between the export request and archive creation may be absent. Nor does an export delete the original data or automatically recreate every service setting in a new account. Those are separate tasks.
What makes it useful
Choose the needed products, download every archive part, open sample files and store the result securely. A full export may contain enough private information to cause serious harm if left in a shared folder. Google's
Takeout documentation describes exclusions, split archives and expiring links. If the data changes regularly, choose a repeat schedule or a separate backup method and perform a restore check.
