I am not sure of the usefulness of this feature. However, I'm never one to flat out tell someone their idea is dumb. I believe this would make downloading bulk nzbs from nzbs . org much more difficult; because the zip file has no particular meaning, it is just a zip file tagged with your username.
With that being said, if people find this useful and it is included... it should be an option. Either that, or detect a specific structure to the zip. Such as, zipping a folder full of nzbs. Even then, I think it would be better left as an option.