Overview
One-shot prompting places too much weight on a single instruction and too much monitoring burden on the user. A loop gives the agent a mechanism for continuing, checking, and revising.
This is especially useful for long-running work. The user can start the task, allow it to work in the background, inspect progress later, and intervene only when necessary.
The principle also reduces the importance of elaborate prompt wording. Short, natural instructions can be sufficient. The larger performance gain comes from defining the loop and the goal, not from making every sentence stylistically perfect.