Once you see how the Sheppard Air software works and the memory aid you will understand why.
There you go. Why learn the material when you can simply memorize the answers?
Given that many companies give written tests during interviews, and many of those take their questions and answers verbatim off the ATP written exam, why wouldn't one start studying early and prepare for success?
Take the "written." It doesn't mean much any more, but where many places want you to have it, why wouldn't you invest the few bucks and get it done?