What is the purpose of a bullet chart?

A bullet chart is designed to visualize the performance of a single metric against one or more related targets or ranges. It efficiently combines a primary measure, a comparative measure (the target), and qualitative ranges (e.g., poor, satisfactory, good) into a compact display. This allows for quick assessment of how well a metric is performing relative to expectations. "Show the total for a single metric" is too simplistic; while it shows a total, its primary purpose is comparison. "Identify a correlation between data points" is incorrect; correlation is better shown with scatter plots or heatmaps. "Highlight a single, critical metric" is partially true, as it focuses on one metric, but it misses the crucial comparative aspect of the bullet chart.