Why was salt valued by everyone? (Other than using it for flavor)

The expression to be worth one's salt, which means you're competent and deserve what you're earning, is most often said to have its roots in ancient Rome, where soldiers were sometimes paid in salt or given an allowance to purchase it.

the pogroms became known as kristallnacht, the "night of shattered glass," for the shattered glass from the store windows that littered the streets. the morning after the pogroms 30,000 german jewish men were arrested for the "crime" of being jewish and sent to concentration camps, where hundreds of them perished.