Effective use of symbols in diagrams is primarily helpful for what purpose?

Using symbols in diagrams serves the primary purpose of effectively showing how a system works. When symbols are employed, they provide a universal language that simplifies complex concepts, making it easier for people to understand the relationships and interactions within various components of a system.

By utilizing standardized symbols, diagrams can succinctly represent functions, processes, and connections without overwhelming the viewer with excessive text. This clarity is particularly beneficial in fields like engineering, computer science, or any technical discipline where visual representation is essential to convey intricate details at a glance.

The other choices focus on aspects that hold less significance in this context. While decoration may enhance visual appeal, it does not serve the fundamental purpose of conveying information about system functionality. Illustrating complexity might be a byproduct of using symbols, but the primary goal is to clarify rather than complicate. Detailing manufacturer specifications, though important, isn't the main function of symbols in a functional diagram; instead, such details are often provided in accompanying documentation or annotations rather than through symbolic representation.