New Smooth is quite handy to deal with rugged shapes. But it is also introduces the new 'dialog-less' approach, when we are basically given a dialog that auto-commits on dropping a selection. Once it is dropped, the change is applied. We will get accustomed to that.

But imagine I smoothed something, then get distracted, and returned to the smoothed path a while after. To undo and reapply this I’d have to go back in History (at least we finally have it).

What if we can apply this as an effect to an object, rather than a immediate filter? It means we can later go back to settings and change the value, and Expand Appearance of it when needed.

Both approaches are usable, so please add it as an effect also.