Most sea water desalination plants rely on the basic principle of heating water to evaporate it, after which the salt-free vapor is condensed. According to Wikipedia, over half the cost of desalination is made up of energy cost, since heating water is very energy intensive. As a back-of-the-envelope estimate, the energy required to bring $1~kg$ of room temperature ($20$°) to a boil under atmospheric pressure is about $620~kcal$. $80~kcal$ to heat it to $100$°C and another $540~kcal$ to bring it to a boil.
Conversely, cooling it down to $0$° takes $20~kcal$ and $80~kcal$ to freeze it, in total $100~kcal$, less than $1/6$ of the energy requirement of the heating method.
This kind of desalination procedure happens in nature - icebergs are largely frozen fresh water. Nevertheless, it seems this is not common in commercial desalination.
Is there a physical reason why freezing water is less suited for desalination compared to heating it?