Thanks for asking this, because I just got mad trying to find it. I am now on vSphere 6.7 U3 (December Patch) and I can't find these settings either. When will this be implemented?

The significance in my opinion is, you go to VAMI enable it and the next time you patch your Appliance, the service is turned off. Now you don't have your dumps the next time something happens, because there is no way to edit the startup policy.