MTK being on 2.6.2 at the moment, and the test i did with three popular kms solutions, to find out which kms solution includes the "nogenticket" regkey, i think i know what activates what
TechNet link is wrong open AVSValidationGP.admx to see the actual registry that's set by the policy not to mention that Classes\AppID\slui.exe is protected registry an can't be modified normally
Only you can decide that. Do you want a 55Mb point and click GUI (MS Toolkit) and all the other functions it offers, or a couple of small scripts for smart KMS activation - a doddle to install/uninstall (abbodi's KMS VL All) - also an install and forget solution. Only you can decide, it's all about user preference as with most software.
I would guess it exists because there would almost certainly be scenarios where a corporate or government policy restricts or forbids information about software licensing or the internal network infrastructure from being sent outside of the company. Remember, it is reporting the DNS, IP and port number of the KMS server. It won't even necessarily prevent people from searching out and using a public facing KMS server. It does however add one more step to the process, and it would only take one user slipping up and not applying the GPO properly for MS to get wind of a public KMS. Maybe that's what they're banking on.