I think what he/she means is poorly designed visualizations. Just because a plot is grayscale and not interactive doesn't mean it's worse than a cluttered poorl

I think what he/she means is poorly designed visualizations. Just because a plot is grayscale and not interactive doesn't mean it's worse than a cluttered poorly-designed super interactive web widget. It's a poor choice of wording, but I think by "overuse" they might mean "unclear but eye-catching". Besides "overuse" is literally the quantity that is excessive.