With traditional 2D CAD, drawings are often out of date and/or drawing views do not accurately reflect the design, leading to expensive manufacturing errors that slow down product delivery. Without an automated update system (like solidworks), all drawing views must be updated manually whenever a design change occurs. 

This becomes an even bigger problem when a component or assembly exists in many different assemblies or at many different levels of the same assembly, because it requires that all the drawing views containing the modified components be updated.