One benefit to this that I would see. Right now, a player can move his token around the screen by clicking and dragging. As long as he doesn't release his mouse button, the move doesn't register on anyone else's system (specifically, the GM's system). However, while the player is dragging his token around, his line of sight is updated dynamically. So, if a, shall we say, less than scrupulous player wants to peek past a door that his party is considering opening, he can get a sneak peek at what's beyond the door by doing this, and then leave his icon back where it was, with no one the wiser. Now, the down side that I can see is more work for the GM during the game. Right now, I create LOS barriers in different colors over doors. That allows me to simply remove that one LOS barrier to reflect the door being opened. With an LOS barrier + movement barrier, I would have to remove them from both layers every time my players opened a door. Granted, not much work, but some. That said, if movement restrictions were based off the LOS barriers already in place, it would accomplish the goals of movement restrictions, prevent the cheating I mentioned above, and not have to make more work for the poor beleaguered GM. Thoughts?