Why is it important to use a fixed common reference point for dimensioning of drawings and sketches?

It is important to use a fixed common reference point on your work peace or drawing to avoid cumulative error, i.e. if a hole is drilled using an incorrect measurement initially, then continuation to measure from the error instead of using a common reference point could result in a whole piece of work being scrapped. Also if somebody has to take over the work, they would need to understand were the dimensions were taken from to enable them to carry on with the work.