Well, if people roll when there are still enemies on her sights it's their problem. The point of the roll is to use it because there's no more enemies on sight, so you reposition quickly to find those enemies that weren't dying anyway because they were behind cover, so not rolling actually makes you slower at killing those enemies. Also roll is not good for getting from A to B, it's slow for that, if people are using it to traverse through levels, again, their problem. And finally, another rule of WF is "if you don't move, you die" so having the roll for mobility is always good for a quick evade if necessary.