Answer:
It can be vitally important. Suppose you are designing a machine. It is not enough that the machine will perform it's intended task. Workers will need to adjust and maintain the machine, as well as operate it. Did you design the needed guarding of moving parts? Is the machine design one that will facilitate lockout of energy during maintenance? Does the design produce unhealthy levels of noise, or air contaminants? What about cumulative trauma, strains and sprains?