ciTools doesn't add anything to ggplot, it creates tidy dataframes that are easy to plot with ggplot. In the example, we show CIs and PIs on a linear mixed model, which ggplot can't handle.

ggplot's has a built in interval for lm that I'm aware of, but there are essentially statistical interval toolkits that you can supply yourself. This lib is a handful of implementations.

Bayesian stats has "credible intrrvals." These are different than those from relative likelihood and those from Frequentist methods.

ggplot's built-in scratch the surface but are still really handy and easy to extend.