There are plenty of reasons to become disability aware in the workplace. Dignity is one reason of course. Each human being is endowed with inalienable rights and their dignity should be honored. But beyond honoring one's human dignity, there are plenty of other reasons.
According to the U.S. Census Bureau, more than 56 million people identify as a "person with a disability." Notice the language; I will address this later. While this number may include many young people with disabilities who have been empowered by the Individuals with Disabilities Education Act (IDEA, 1975) and the Americans with Disabilities Act (ADA, 1990), it does not include, for instance, many of the 11,000 people who are reaching retirement age every day in the U.S. These baby boomers just can't see as well or hear as well as they used to, but do not identify as people with disabilities.