[Mattasher]

There is an advantage of using pie charts when you have lots of categories, especially when some are tiny slivers. It's that you can see which items are negligible in terms of their relative contributions. A world GDP pie chart gives a good representation of how international GDP is distributed, and which countries represent only a sliver of the total.

EDIT: Typo

[riddley]

Wouldn't bar charts show that too but without the issues mentioned in the article?

[Gormo]

A bar chart is better at showing each individual value independently (and perhaps in relation to its neighbors) but is worse at showing each value as a proportion of an overall aggregation.

[adrianmonk]

Yes, you can visually add slivers. Just ignore the boundaries between them, and boom you've added them.