You noticed, that this thread is from 2008?

Molebox is not simply a filepacker with encryption - it is a protection for your game assets. Most model packages Eula require that you protect their models from being extracted from your game.

If you use a filepacker which unpacks the mdl-files into a temporary folder, it might be nice to have a single .exe file only, but you might get into trouble if you sell the program and it is easy to rip the models out of your temp folder.

I use molebox for models, sounds, etc.

How does molebox work?
It redirects file handling system calls to use their own function calls which can handle the encrypted archive. Your program can be limited to only work with files from your archive, and lots of other options can be used to make your program a bit harder to crack.