I’ve always thought that it was the warmer (relatively) utility water that made dripping faucets so effective. But I actually appreciate this framework better.
You’re Letting Your Faucets Drip Wrong in Winter
When the water in your pipes freezes, it expands, stressing your pipe. If you have all the faucets closed when the water starts to melt, it will have nowhere to go, so it will soon create somewhere to go. Having a faucet open gives that water a release point, which can save your pipes.