Yeah, if you're using a program that REALLY knows how to work with the tablet, and doesn't just treat it like a mouse, it is quite accurate.
Remember, the tablet can sense where the pen is when it isn't touching it. I'm pretty sure the tablet gets a lot of its precision by sensing exactly how close it is to its various sensors, delivering an analog measurement for higher accuracy.
I don't know this for sure, but it just seems reasonable to me.
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