Worker mode biggest benefit is not that you can export with it or not, but possiblity that some bad loop etc does not crash your editor, resulting you loosing a lot of work. Now it stable enough to keep it constantly on.
Gameplay seems a bit smoother with worker exports, but its Dt is not constant and also varies depending on browser so very smooth lerps/tweens etc could show some jankiness, also it's same with other browsers even when there is no worker mode.
Not related but.
What Nepeo said "VERY high spikes when you cross a loading threshold"
This is pretty awful, sometime it feels like there is small spike(1-2 tick) but it somehow overflows into ~0.2sec. Not sure what causes it.