How did demilunes slow attackers during a siege?

In the context of early modern military science, demilunes were semidetached outworks positioned within the ditch between bastions. They served as a critical component of the bastioned trace, a design strategy developed to counter the increasing power of heavy artillery and the larger armies of the 16th and 17th centuries.1

Demilunes slowed attackers by acting as a defensive buffer that shielded the main fortress walls from direct enemy battery. By forcing besiegers to contend with these elaborate outworks before reaching the primary fortifications, defenders could significantly delay the attacker's progress and increase the cost of the siege in terms of time and resources. This integration of outworks, often associated with the engineering principles of Sébastien Le Prestre de Vauban, allowed fortresses to adapt to the evolving lethality of gunpowder weaponry.12