So why pay off your old bills if it doesn't help fix your credit score?

So my husband and I are wanting to fix our credit. We are 6 points away from buying our first home. Thankfully, we are able to raise it 10 points to get the house. Now we are going through and paying off old bills that we have, but it's so discouraging to know that as we pay them it's not going to help our score what so ever. So...... What's the point????