Back in NW this feature was pretty useful for securing a server (if unapproved people had the admin password, logged into the server, they would get auto perm banned.) However it had it's annoying aspects such as;
Inputting player ID's: It was a pain to do, you had to edit a text file in the server folder, look up the area of the text files to put in the ID keys (often an eye sore), not knowing who's ID's belonged to which person. + Improve/add a admin list interface.
Required server reset: Admin teams will often change, admins ID's will be required to be added or removed. Server reset was required to make changes which was annoying for public server hosters. + Make changes not require a server reset.