Softens water to avoid watermarks on dishes.

There are some people who skip these additives when using the dishwasher on a daily basis. Is this a mistake?
Rinse & Shine Aid helps to:
Salt helps to:
Rinse aid helps to ensure spot-free, shiny dishes and assist in the drying function. If you live in a hardwater area, Salt helps to protect your machine from limescale, and soften the water for better cleaning. In very hard water areas it is recommended to use both Salt and Rinse Aid products to protect your machine and achieve the best results with your dishes and glasses