There's a big difference between being able to stand up and move your arms, and being able to stand up and move your arms anywhere without looking while being certain not to hit anything.

At least for me, in all the spaces I have computers, if I stand up I have some stuff or shelves within arm's reach, because I want that stuff to be accessible - but that makes those spaces unusable for VR, because I'll hurt myself those things or myself if I'm swinging around without being able to see what's there.