FontCreator already has a smoothing filter, but I still need to use time-consuming workarounds like this for smoothing curves after autotracing or manual drawing. I spend ages reducing nodes and smoothing curves in my fonts.
At least, we need some feature that will autoreduce nodes, but Spiro does more than that. In effect it makes each on-curve point into a smooth node.
The other thing it has is a brush-like feature for drawing variable width curves. A brush that would allow the drawing of uniform strokes would also be very useful in FontCreator.