The reason I ask is because if you are calculating times for animation tracks, you can just get the current time and use that as a reference point for local animations. I've done this and it seems to work pretty much spot on for animation timings, no matter how long your frame time is.
What happens if your game freezes for an entire second? Whether or not the animation is correct, the world will have advanced a whole second and the user will be confused about what happened in that time. For simple problems, maybe one doesn't need a fixed time step, but there should at least be a maximum allowable amount of time to pass in one frame.