This was largely notable because now, Jim Corrigan and the Spectre became two separate entities (although the body of Jim Corrigan was, in fact, a piece of the Spectre's ectoplasm, as later revealed). The body of Corrigan still served as a host to the Spectre, but the Spectre could move on his own separately for a whole day, afterwards needing to return to Corrigan's body to replenish his energy. This allowed for Corrigan to actually team up with the Spectre (rather than the two being one), in essence splitting the 'workload' in two, since one could handle research and the other could get the job done. It also allowed for Corrigan to become a full-fledged detective again.