I think they just stayed the decision to give the regime a little time to file an appeal before the order went into effect. Which in a functioning democracy with a functioning federal court system, would be what you want. A reasoned decision after the feds get their chance to argue their case. And if the feds still lose, then you have a strong record before it possibly heads to the Supreme Court.
In this world, though, it doesn't really matter either way. Regardless of whether the regime suffers a temporary setback tomorrow, there's going to be bloodshed. We're less than five months into the trump regime and this is already where we're at. By the end of summer, the trump sycophants (which includes large swaths of the military and the police) will have forcibly invaded and taken over California, or California will have left the union and there will be civil war. Assuming the upcoming WWIII didn't kill us all first.