It has to go through the appropriate legal channels first though. It's not like this will be appealed, argued, and ruled on at the Supreme Court level within a week. An injunction will be in place immediately but a ruling from the High Court would most likely take several years. By the time it's appealed either through the Federal district courts or the State courts and makes its way to the Supreme Court the makeup may be different than it is now. It's not unlikely one or two justices (most likely Ginsburg and Stevens) will retire within 2-3 years.
Remember also if the Supreme Court isn't in a favorable configuration South Dakota doesn't have to appeal up to the court for a precedent reaffirming setback. This seems like a positioning move, a set up for a challenge to the fundamental holding of Roe years later.