I don't know what I wrote that makes you think I started with the premise that you're a novice, I had no intention of sounding that way. Comparatively, I'm the novice.
With any advanced functionality the trade-off is either programmer time or CPU time. If you don't need OO (or it isn't a standard bit of the language), I certainly wouldn't warp my problem domain to fit into OO. But the amount of overhead depends on the language. In some it's going to add a lot of overhead, in some not much. But if its not going to save the programmer time, why use it?
You're right that Perl isn't designed to teach OO, it's barely designed to do OO. But I like it because everything is so exposed and a little bit hard-- that way, instead of relying on the magic of the programming language, I have to understand what I'm doing. Maybe that's not the best way to learn it. But I don't know that there's any right way to learn anything. Most things just take time and practice. I don't think if I were serious about using OO for a project that Perl would be the language I'd choose.