This is intended to benefit civilian and military servicemember who are sent by the USG for a job/mission for a term over 365 days to be released from paying state taxes while not residing in their state of residency.
Presently the USG stations many civilian employees and military members overseas. Depending on the state tax laws, non-residing residents are made to pay state taxes as if they were residing in that state. This is an unlawful and unfair practice of certain states (not all) that mandates all state residents, with only as little as a state driver's license, to pay thousands of dollars a year without utilizing any of their state services, without residing or owning land there.