In wca4z validation, why is business-side user acceptance testing (UAT) important after technical testing passes?

Think of it like working hands-on with IBM mainframe systems — the answer here is 'UAT is required by IBM to issue the final wca4z transformation certificate for the program'. Even after technical equivalence is proven, UAT ensures that the new Java module meets business stakeholder expectations in realistic scenarios, catching functional gaps that purely technical tests ma. On real mainframe exams, this concept comes up repeatedly so make sure you have it locked in.