If you have hard water then the attraction of proper water treatment would be less wear and tear on your plumbing, appliances, and fixtures resulting in a longer service life with fewer repairs and less frequent replacement. Clothes would last longer and you'd use less soap and detergents.

If your water has a low pH it will be aggressive interacting with your plumbing and fixtures and appliances.

If you have iron and manganese in your water then the attraction of proper water treatment would be no stains on your clothes and in your appliances.

If you're on a well and have bacteria or nitrates then the attraction of proper water treatment would be a better health and an undoubtedly happier life. Neither Giardia or Ecoli or Norovirus are pleasant experiences.

Softeners are only one aspect of water treatment. In order to understand the attraction of water treatment you'd need to know what is in your water and what the consequences of living with those contaminants would be and then deciding if you want to or not.

Water is VERY important. We drink it, wash food with it, cook with it, and bathe in it. With water what you don't know can hurt you and cost you money. A comprehensive water test is a good investment.

If you don't understand why water softeners are so popular you probably have never lived in an area with hard water. High mineral content (hard) water builds up white gunk on all the fixtures and sink spouts, prevents detergent from cleaning as well, and makes your skin feel very dry/sticky.

Soft water also has its problems (salt content, slippery feeling skin, etc.), but most are more tolerable than what you get with hard water.

Bruce