In this article you will see how being a G Suite Administrator you can get a copy of your users sent and received emails without knowing their passwords or putting forwarding in their mailboxes
Got it now. Getting a copy of incoming + outgoing via BCC for an individual account's emails is not quite the same as accessing individual account's emails though.
For GSuite basic subscriptions, there is a 30GB quota per inbox, having BCCs for every account's emails will like exceed the plan allowance. I doubt it would work if you exceed the account quota allowed for the subscription plan.