Any application that has an intended end user is nothing without that user, regardless how reliable, how functional, how flexible it might be, so usability issues matter (ā¦even when some upper-level manager only cares about sales numbers, and lacks the perspective that any user base that isnāt made up of a retained user base is a burning user base, and with churn may one day result in them having no new users).
Holistic approaches understands that context matters, that shallow attempts at validation may tick boxes with meeting requirements, but a user is rarely that shallow, requirements is not really the domain of those using the application, they are just trying to either work out how to do something, see if something is possible, or reach a particular goal. Shallow approaches, and likewise purely tool-driven approaches, will leave voids that your users will fall into.