The registration process is not that difficult. Most of it is filling out company info (name,address, etc.). There is only one part that asks you about your encryption. The process takes about 3 days and a few back-and-fourths.
Apple has the checkbox in iTunesConnect to mark if you use encryption for anything other than sign-in credentials. It appears like they are just covering their butts. You submit a screenshot of your completed form and they sign off on it right away.
For an outline of the steps you need to take see:
https://www.chatmap.io/blog/iPhone-iTunes-ERN-Encryption.php
In short, it's not a great deal of work to register.