1. If I want a confidence interval, I want to know the end points of the confidence interval. Trying to guess them from a plot like this is annoying and not helpful.

2. This doesn't work for bar graphs, lengths, etc. The uncertainty is often going to be symmetric around the point estimate, but your opacity forces an asymmetric representation of the uncertainty.

3. Box plots are great. If you want more detail than that, a thin vertical histogram or density is going to convey much more information than shading.