StatusBar update smoothing is a feature of WeakAuras that makes the jumps in resources less abrupt and more gradual, albeit over a very small period of time.

@LucasCH13 pointed out a library, LibSmoothStatusBar-1.0, that is used by a still working WoD-era addon to Shadowed Unit Frames that achieves this and could also be implemented in the bar.

Add this and make it a global optional feature.