I recently reviewed the excellent BytePac, allowing you to store and access old hard drives via some simple cardboard packaging.
Now, they’ve documented a simple method to download the entire contents of Wikipedia and add them to a BytePac connected drive. They’ve even provided a template that you can print to add a Wikipedia themed cover to your storage box.
Is it worthwhile? That’s down to you. If you have a need for an offline version, then it’s a great idea, well documented. Personally, I think I’m happy with the latest online version.