It' s worth the bother if you are going for fantastic groups (which I happen to like
) or plan to shoot at very long range. For normal BP hunting ranges, the volumetric measure is fine. Consistency is the key to good accuracy either way.
The way I approach this is by throwing a hunting charge by volume and then matching the weight of that charge for each subsequent charge on the scales. Keep a few of the pre-weighed charges in my speedloaders for hunting or several in individual containers if going to the range. Using that method if I run out of premeasured charges, my powder measure will throw a near equal and similar performing charge. Hope that made sense!