Without it, we'd still be living in huts and hunting prey, because on an absolute basis that is way better than sleeping under a tree in the cold.
It's the thing that lets a child enjoy watching a lion at the zoo, behind glass, angrily advancing and pawing at them.
It's the thing that makes a billionaire keep working hard at the next big thing, despite them having enough money to not care.
Our inability to be perfectly happy and content with our situation, in an oddly confusing way, is what makes us so great, what makes us continue to strive to make things better, and get out of bed every morning to continue advancing humanity.
They don't care if you are happy or not, as long as you are potentially reproductively successful. They are so stupid they can't even tell the difference between drug-based euphoria, or other addictions, and genuine success. And our genes don't even care if the entire ecosystem collapses underneath us, because the whole species is acting the same way.
Sometimes this restlessness does "advance humanity", but that's not inherent in what our genes want. It's only because we have carefully set up institutions and practices such that the best way to compete is to serve other people.
But, barring the discovery of some infinite source of non-polluting energy and materials, at some point - either tomorrow or in a thousand years - this restlessness will have to be tamed. In short, there are limits.
And for individuals, those limits are much nearer, and the benefits of controlling your desires are as well.