I am assuming you are asking about the time before the Civil War. If so, the major importance of this issue is that it helped to push the North and South apart, with each side deprecating the other's treatment of its workers.
During the antebellum period, both the North and South criticized the other. The North argued that the South's treatment of slaves was brutal and inhuman. This was one of their arguments against the expansion of slavery. In response, the South argued that Northern workers were mistreated and that slaves had better working and living conditions and were more likely to be well cared-for when they were sick or old.
In this way, the conditions of life and work were an important issue in American politics during the antebellum period.