Player saying "I'm going to open the door"
GM - "How far"?"
Player "1 foot, slowly"
GM opens door 1 foot.
Player "OK, I'll open it another foot"
GM opens door another foot.
You may like that level of 'control' as a GM, but I don't. When everything was done with words, that's the way it had to be. Doesn't really have to be like that now.
And I don't want to have to be drawing and erasing VBL lines just to open a door. That is something that can be automated as part of the door object. I want to be free to concentrate on the game too, not spending my time concentrating on working the technology.