Pie charts shine when there several data points that can be grouped into 2-3 macro groups.
The easiest example is "What is your opinion of ___?" (Strongly Favorable, Somewhat Favorable, Neutral, Somewhat Unfavorable, or Strongly Unfavorable)
At a glance, you can see if the opinions are positive or negative, and then can see if they are polarizing or mostly neutral.
Another example would be the makeup of congress. Democrat, Independent, and Republican for the major groups. Subgroups could be based on percentage of votes the person received from their district. It would show which seats could swing.
The easiest example is "What is your opinion of ___?" (Strongly Favorable, Somewhat Favorable, Neutral, Somewhat Unfavorable, or Strongly Unfavorable)
At a glance, you can see if the opinions are positive or negative, and then can see if they are polarizing or mostly neutral.
Another example would be the makeup of congress. Democrat, Independent, and Republican for the major groups. Subgroups could be based on percentage of votes the person received from their district. It would show which seats could swing.