Originally Posted by JSWolf
I'm already at the external ToC. Why would I then want to go to the internal ToC (which has no use at all in an ePub)?
Because the internal ToC may have additional information like illustrations, summaries, authors/dates...
Of course, it could happen that the internal ToC is simply a duplication of the external one, in that case I agree with you. But my point is that an internal ToC is not necessarily a bad thing.