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  • Tammy LaBiche-Henley thinks this is interesting:

Stacked bars make sense here given the nature of what is being graphed: top priority (in first position in the darkest shade), 2nd priority (in second position and a slightly lighter shade of the same color), and 3rd priority (in third position and an even lighter shade of the same color). Orienting the chart horizontally means the category names along the left are easy to read in horizontal text.

From

Cover of Storytelling with Data: A Data Visualization Guide for Business Professionals

Note

Horizontal stacked bars to show 3 priorities with the most important on top and reading from top to bottom, left to right, dark colors to light colors and grey on bottom