Which of the following is a primary benefit of water mist systems?

The primary benefit of water mist systems is that they effectively use less water while controlling fires. This technology works by creating fine mist droplets that have a larger surface area relative to their volume. When these droplets come into contact with heat or flames, they absorb heat and evaporate quickly, which helps in suppressing the fire more effectively than larger droplets from traditional sprinklers. This efficient use of water not only helps in extinguishing the fire but also minimizes water damage to the structure and its contents, making water mist systems particularly valuable in environments where water-sensitive materials are present.

In terms of other aspects, while water mist systems can represent a cost-saving measure in some cases, they are not universally less expensive than traditional sprinklers. Maintenance levels can vary depending on system design and local regulations, and it's not accurate to say that they require significantly less maintenance compared to traditional systems. Lastly, water mist systems are not suitable for all enclosed spaces; their application is specific and determined by the fire hazards present in a given area, which makes option D incorrect.