A tax benefit works only if the person has income to offset. If you are a freelance developer and you get sick with a life threatening or chronic illness or even just injured, you may not be able to work while you are getting treatment. If you want more job freedom, a needs based subsidy based on tax income allows cost shifting from years of productive work and tax earnings to years where you can't work, even if your productive work comes later in life, after treatment.

It also provides for those who may never be able to earn enough working to pay for current health insurance, those who are retraining latter in life, and those starting a company.