Yes that's exactly what it did, it kept us from seeing $10/gallon gas at the pump which would be immediately catastrophic to the entire American way of life. Even with $5/gallon gas like now and earlier in the summer we have seen pretty dramatic inflation in food and goods--diesel is enormously expensive and increased trucking costs just push up the prices of goods higher.
So now imagine what's going to happen when that is turned off, and even worse when the oil market sees pressure from the US buying millions and millions of barrels to take them off the market and throw them back into the reserve...