It’s a requirement imposed by Oculus. Within 4 sec of app start user has to have stuff on the screen. So, either way you have to have a black box map and 3D widget. You don’t have to have “menu” level and can proceed to the main level after black box room.
You won’t be able to load main level in 4 sec. and you can’t have 3D progress indicator without 3D widget, which has to be in some kind of 3D environment. Thus, black box level with 3D widget and streaming main level is the only proper way of complying with Oculus and providing non-sickening experience to use.
The reason I brought up “menu” map into equation is that having black box room and progress indicator in VR for more than 10-20 sec is annoying and horrible. So might as well load “menu” level where player can begin interacting with VR environment, while main level is being loaded than have player stare in the blackness (or any color for that matter) until main map is loaded.