If all a user needs to do is extract files individually or collectively from a container and place them into the filesystem--which may well be the requirement for 80% of the uses of the containers--he doesn't need to use the API!

I'm not so sure I agree with that. What if the user wants to extract files based on complex criteria? What if the user wants to automatically extract files received via web upload forms? What if the user wants to extract the files from many archives at the same time?

Certainly, some of these things can be solved by shell scripts or otherwise, but doesn't Perl sound like an attractive solution too? Having an API that makes these things simple, while still having all the power of Perl around it, seems like a benefit to me.

Added a few minutes later: sorry about jumping in so deeply into the thread. I thought it would be useful to add to the conversation. But now I wonder if anyone will even see it. =^)