Significant digits reflect true precision of a calculation but sometimes it is important for measurements to be?

Answer 1

Significant digits do help to reflect the true precision of a measurement. This is because often the last reported digit in a measurement has an unacceptably large error associated with it. Thus, only reporting significant digits is the most conservative practice. Sometimes, however, it helps to be more accurate on a single measurement. In this case, if the measurement device is reliable to the last reported digit it may be reported for the sake of accuracy.