I think  is making a distinction between IS and OUGHT. Activities within a process SHOULD add value, but sometimes they don't. Within BPR, people often make a distinction between "As-Is" processes and "To-Be" processes. Perhaps it would be useful to make this explicit within the article. 

However, complex processes may include activities whose value-add is obscure or difficult to quantify. For example, a salesman carries out some social chat prior to demonstrating the product, and this possibly converts the customer to a more receptive state. A craftsman may play around with the materials before starting construction, which may possible put him into a more creative/innovative state. But do we really want to engineer every business conversation or playful bricolage to optimize some desired state-transition? This is BPR not NLP.