In a team inbox you can press the archive and the e-mail will be marked as closed and archived. You will now find the conversation in your unified mailboxes under closed. In your private inbox you also have the same symbol, but this symbol does not do the same as if you answer mails sent to a team-mail. So if you work in your inbox and answer or archive several e-mails the same button in the same inbox might not do the same.
We would like the archive symbol to close and archive just as the symbol does when you answer a team inbox mail.