...Using this, you can test whether your applications can send emails correctly, and you can retrieve the data out of them (for example if you need to verify that account activation links exist in the outgoing email, and that they work correctly).
The real Mailinator service is better if you are only sending a one-off email. Likewise if your company wants to test emails then they may be better off speaking to Mailinator about commercial offerings. This project is designed for the small developer.