In teaching SAS Education courses in Australia over the years I've found myself saying on each programming course that there appears to be 2 groups of SAS programmers... Those that do SAS programming and those that understand SAS programming. One can copy and paste SAS code for years and say they are a SAS programmer however they may not fully understand what is happening at compilation and execution time and spend a lot of time debugging. However, a programmer that understands these concepts including how the PDV works will be more productive in their SAS programming with less debugging as they can forsee how the code will be compiled and executed.

A great post to highlight why it is important to know the fundamentals of SAS programming and the PDV.