Curious about this design decision in CustomerMaint.cs

In CustomerMaint.cs the Customer_RowInserted method uses a boolean needUpdate to decide if the cache is going to be updated.  I’m curious to know why it doesn’t just call Update regardless.

		protected virtual void Customer_RowInserted(PXCache cache, PXRowInsertedEventArgs e)
		{
			bool needUpdate = false;
			Customer customer = (Customer)e.Row;
			if (customer.DefBillAddressID == null)
			{
				customer.DefBillAddressID = customer.DefAddressID;
				needUpdate = true;
			}
			if (customer.DefBillContactID == null)
			{
				customer.DefBillContactID = customer.DefContactID;
				needUpdate = true;
			}

			if (needUpdate)
				this.BAccountAccessor.Cache.Update(customer);

            CustomerClassDefaultInserting();
        }