I did a lot of reloading with a GemPro scale. Throw a charge in the ball park and manually trickle up to weight. 0.02 grain precision. And, I could throw and trickle faster than my chargemaster dispenses. But, I can do other things while the chargemaster is working so I am more efficient with it, even accounting for its slowness.
The gempro is quite adequate, and precise, though a very manual process.
The chargemaster is more automated, freeing you to do something else in the minute or so it takes to throw a charge. But, it is only +\- 0.1 grain.
Lots of people are perfectly satisfied with the beam scale included in the RCBS rockchucker starter kit.