I was disappointed to see they use Ultimate Guitar data for this. Back when I played regularly under the study of a professional, I quickly found that the majority of tabs on the site are just plain wrong.

Likely some of the “simplicity” observed in the chords here aren’t actually due to the music being simple, but that the user who contributed the tab made their best simplified guess as to what it was.

Unfortunately the analysis is probably flawed because of the poor quality of data.