Why would you make line plots, with a category variable on the x-axis? Bar charts would be appropriate here. Also, the lines seem to have way more line segment

Why would you make line plots, with a category variable on the x-axis? Bar charts would be appropriate here. Also, the lines seem to have way more line segments than there are labels on visible on the x-axis, so what do the graphs even mean? Are they based on a larger number of instance types than what the labels show? What are those non-labeled instances then?