I think it's nice that folders can be hidden from the menu by simply putting a . (dot) in front of them.
What's even better tho', IMHO, is the fact that you can still reference and access them, say from an direct HTML link within a page!
This works very nicely if you'd like to have archived pages or galleries which are not available within the main menu, but still deep linked from another place within the site.
The only odd part is that they are also not visible within the admin module once the DOT is included in the folder name. No biggie, though, as they are still accessible via FTP.
Very Nice -;)
Kudo's Muaj Mauj and Pain!