I dunno about being more accurate, but the digital ones are way easier to use. The beam balance ones show nothing untill you are there, and then it is too late and you usually have overshot and have to start taking it out again to get it to balance
But then, a short story about scale accuracy...
I work for a large large military electronics company, and we have all sorts of scales all over the place.
At one time we were making handgun ammo for the military, and we used a common Lyman beam balance grain scale to measure powder charges. The ammo-making is long since history, but when the project ended I confiscated the scale and put it in my office. It is still under "calibration control" and is checked for accuracy twice a year by our calibration department.
Out of all the fancy scales we have in our facility, every time they calibrate the Lyman powder scale and bring it back they tell me it is the most consistantly accurate scale we have in the building.
Rick