Temporarily capture unattended email
You don't want to configure email for every domain you run.
You don't want fiddle with SPF, DKIM, configure postmaster and abuse inboxes, Mailserver, etc.
Sometimes though, you need to capture just one email, for that one off time perhaps a few times a year.
Set your MX record to point to MX:BIN, run one-time verification, and activate your domain as you need it, for free.