In a Las Vegas address, Obama offered to create a form of provisional immigrant status for many of the estimated 11 million undocumented residents of the country that would allow them to stay legally and potentially earn citizen status over time. The president's plan came one day after the introduction of a similar plan from a group of bipartisan U.S. senators.

But there are some financial and policy incentives to give legal undocumented residents access to health insurance through state insurance exchanges, said Sonal Ambegaokar, health policy attorney for the National Immigration Law Center, an advocate for low-income immigrants and their families.

The relatively young and healthy population of undocumented immigrants would be sought after by the insurers in the exchanges because they would help keep costs down, Ambegaokar said. "We need more people paying for insurance," she said.

In addition, Ambegaokar said it might seem unfair that U.S. citizens would be required to buy insurance under the mandates of the ACA, yet provisional legal residents would not be required to do so. "If we continue to exclude them, we're sending the message to others that they don't need to get covered either," Ambegaokar said.

Dr. Georges Benjamin, executive director of the American Public Health Association, said that from a public health and economic viewpoint, it would make sense for provisional legal residents to be covered by the healthcare law. "In those states where there are a high number of immigrants who are working, I would think you'd want to cover them," Benjamin said.

"A lot of the industries these folks are working in are high risk industries," he said. "You don't want sick workers."