In the Bible, why would God turn someone to salt instead of smiting them?

Genesis 19 tells the story of the destruction of Sodom and Gomorrah. Lot, Abraham’s nephew, lived in Sodom with his family. His daughters were engaged to local men. Lot was sitting at the gate of Sodom, the area where financial and judicial transactions took place, when two angels came into town. Lot invited them to stay with his family. The angels made sure Lot…