Of course most solids are denser than the liquid at the same temperature. The crystal is more densely packed than the liquid. Water is different because its polar molecules line up (hydrogen bonding) when it crystallises (freezes). The resulting lattice is a more open structure than the chaotic liquid, which has enough energy to disrupt (most of) the hydrogen bonds. It is one of the features that has made Earth life possible on Earth.

Life as we know it couldn't exist without that feature. Which isn't at all the same as saying that life couldn't exist without that feature.