You might not have heard it, but I don't think anyone here is laughing at you :) Actually, the reason you haven't heard it is that it isn't happening. That's a big plus for this site in my book.
in reply to why use a hash instead of an array
About your question, I couldn't add much at this point because I haven't had a need for hashes yet. Not that I know of...
Regarding learning Perl, I think If you're going to do this you could do better than trying to pick it up piecemeal as you need parts of it. There was a thread recently about an instructional book series. There are three of them, starting with Learning Perl, then Intermediate Perl, and finally (coming out in August) Mastering Perl.
I'd been trying to piece together programs using a sort of reference, Programming Perl. I've found that it's helpful, but tends to dash around a bit since it's not meant to be an instructional text. Which is why I picked up and have started on Learning Perl yesterday :) Once I get to chapter 6, I'll no doubt start seeing uses for those hashes...