If misfortune strikes hard and you become disabled, you could not only loose your job, but also your ability to provide medical coverage for your family.
Public health insurance (Medicare) will currently cover the newly disabled under 65, however it will not cover their spouse or their children.
This means if the main income provider employed in your family becomes seriously ill or injured, they will loose their job and their spouse and children will loose their group health insurance coverage.
Medicare premium bills are much cheaper than paying for a private health insurance policy by thousands of dollars a year.
American citizens should not loose everything they have worked hard for because of an illness or bad-luck injury.