According to the Federation of American Scientists, the B61-12 will be able to strike within 30 meters of its target. This accuracy allows the bomb to destroy targets that would have previously necessitated the use of a larger but more indiscriminate weapon. As a result of the bomb's relatively low yield, the weapon would produce less nuclear fallout than earlier nuclear weapons, something which would limit unintended casualties from a nuclear attack.
But this lower fallout also lowers the cost and scope of a nuclear strike -- which could in turn increase the possibility that the bomb would actually be used in a military engagement.
As it is, the B61-12 may actually expand the range of possible US nuclear targets. In a 2014 conference organized by the Stimson Center, retired US Air Force General Norton Schwartz said that the B61-12's target set goes beyond that of previous gravity-guided nuclear bombs in the US military. This effectively means that the US could now consider the use of aircraft-delivered lower-yield nuclear weapons in a wider range of scenarios.