To me, it wasn't that I could use Safari that was killer app, but the fact I can use it as a monitor that impresses me. I don't think most VR setups allow you to read text as easily as on a monitor and that is what Apple is claiming. (First impressions seem to support). The second part is not requiring a controller. If I can control this with my eyes, hand and voice. That means I can use a keyboard with it. I assume they'll have some virtual version too. With those two things, a whole lot more use cases open up around it. I don't plan on getting one right away or anything, but an actual usable computer is far more interesting than something that plays games, moves some models around in space and does video conferencing with avatars.