The main question would be as to it's stability. If it is stable then it is useable. I really don't know what 'accuracy of 0.2 pH' means. I suspect that it means that the reading in a calibration buffer wanders such that it rms value is 0.2 pH. You can easily check the stability by simply making repeated readings in one of the buffers over time and writing them down. If the device reading doesn't change over a period of half an hour or more it is definitely useable. Even if it holds for only 15 minutes you can use it but you will need to recalibrate it each time you take a reading. And that would give you a better picture than papers.