What is the importance of the number of children living in Australia in a parent visa application?

For a parent to be eligible to apply for a parent visa, the parent has to pass the balance of family test.  The balance of family test is satisfied if the parent has each of his or her children either lawfully and permanently resident in Australia or who is an eligible New Zealand citizen and usually resident in Australia: or the number of children of that parent lawfully and permanently resident in Australia or eligible New Zealand citizen usually resident in Australia is greater than or equal to the total number of children of the parent who are resident overseas or the number of children of the parent who are lawfully and permanently resident in Australia or are eligible New Zealand citizens usually resident in Australia is greater than the greatest number of children of the parent who are resident in any single overseas country.  e.g. a parent who has all children lawfully and permanently resident in Australia will pass the balance of family test.  A person who has 5 children and 3 of them are permanently and lawfully resident in Australia will also pass the balance of family test.  A person who has 5 children two of whom are permanently and lawfully living in Australia, one is living in New Zealand, one is living in Fiji and one is living in Pakistan will also pass the balance of family test.  However, if a parent has 2 children lawfully and permanently resident in Australia, 2 lawfully and permanently resident in New Zealand and 1 lawfully and permanently resident in Fiji will not pass the balance of family test.  A parent who has 2 children and 1 is lawfully and permanently living in Australia and the other is living in any other country will pass the balance of family test.