Email has been a simple and reliable tool for decades. However, there have been many simple methods to use email as a tracking device.
Often links to images will be embedded into the body of a message. Your email client will then fetch those images when it is opened. This process informs the image provide when and where you viewed the email. The email is tracking you.
When an email arrives at a ShofarNexus email server, these links are found and the images are downloaded and embedded directly into the email. The tracking remains, but the information provided is that of the email server and at the time sent. When and from where you read it, irrespective of the email client, you are no longer exposed, you are no longer tracked.
By default, any script is quarantined in the email. It is not lost, but will not run.
The email become a simple static file and not a program that runs on your machine for potentially invasive purposes.