Pie charts, despite their ubiquity and criticism from prominent figures, can be an effective data visualization tool when used correctly. They have limitations, such as difficulty in interpreting precise values without data labels or being able to compare overall amounts. However, by following five principles - emphasizing key data points, strategic use of color, utilizing data labels, meaningful titles, and maintaining simplicity - pie charts can be made more interpretable. Another type of pie chart, the doughnut chart, is even easier to interpret because it prompts the viewer's gaze to traverse the circumference, allowing for a better judgment of linear distances. Pie charts can also be useful in spatial data visualization, such as in Cannibalization Analysis, where they help compare market sizes and provide additional context with widgets like the Pie Widget.