The Affordable Care Act (ACA) was pushed primarily as a way to extend health insurance coverage. This was, and is, an important goal.
However, another important aspect of the ACA is its impact on the labor market. The vast majority of people who are below Medicare age get their insurance through their job. This meant that tens of millions of people felt tied to a job because this was the only way they could get insurance for themselves and their families.
A key feature of Obamacare is that by allowing people to get insurance through the exchanges, workers would no longer feel tied to their jobs in the same way. Workers that wanted to look for jobs that may be a better fit, or wanted to try to start their own business, or just hated their boss, could now take this step without worrying about losing insurance for themselves and their families.