Currently each share must have associated Guest / recipient (email address). It is not required to send a message to this email, but it's an option.
However sometimes you would like to have "anonymous" share, which you would share via IM on social networks or by some other way. You can do it now by using your own address for a Guest email, but what about not having email mandatory and simply have option to create anonymous share.
It makes sense for sending files, but what about requesting a file?
