Within lean initiatives, Time is the most important factor. The efficiency of a value stream is measured based on Lead times, for which you need process time and waiting times.
The effectiveness of the value stream is calculated by comparing (actual) cycle times with the Takt time.
Knowing the different times and the goals for which they are used can prevent long discussions at value stream events. It is therefore advisable to define each term before you start mapping, especially because different organizations use different definitions of the terms.