Higher productivity helps keep prices down and wages up. It gives workers more money to spend and increases the value they get when they spend it. And it allows businesses to weather cost increases without having to raise prices. All together, these factors drive economic growth.
Labour force participation tells us how many people are active in the labour market and how many have dropped out of it. It is just one piece of a larger puzzle, but it is essential to understanding what is happening in the labour market overall.