To ensure correct total calculations. Frame the concept in practical terms so you can explain it during interview discussion.
Accumulators, like a total price, must start at a known value, usually zero, to accumulate values accurately. If not initialized, they may hold garbage values and lead to incorrect totals. Example: int total = 0; for(int i = 0; i < cartItems.length; i++) { total += cartItems[i].price; }.