You learn in quant class (quantitative chemical analysis) that the scales (okay, really sensitive ones) will mis-weigh an object if you have finger prints on it. If your fingers are unclean, I'd think even a powder balance would benefit from wearing rubber gloves or handling with tongs. With a high end, accurate, enclosed single pan balance, you can see the weight drop on a small flask or glass object after you set it on there with your fingers as the fluids from your finger prints evaporate. So, SOP for gravimetric analytical techniques is to use tongs to handle such when weighing, wear gloves, don't get anything on the object to be weighed or it will have a negative affect on the accuracy of your test.
I really don't see much of an affect with a balance that only weighs to 0.1 grain, though. Just something to think about when talking about weight drift. What I like about the electronic balance is that I mostly load with volume powder measures. If I want to weigh every 5th round, I just tare the case, dump the powder, weigh it in the case, keep loading. Much quicker and simpler than working with a beam balance. I load ALL my handgun ammo with powder measures and most of my rifle ammo. I'm a hunter, far as rifles go, not a bench rest shooter. I don't sort cases, bullets, that sort of thing. I still get 1 MOA or sub MOA from my handloads. If I wanted those quarter MOA one hole 100 yard groups, I'd worry about weighing every charge and that sort of thing.