Schick allows you to transfer files over Rendezvous network. I wanted a simple and fast way to exchange small files, like Word-Documents, Pictures, URLs, etc.
iChat and similar tools need much configuration and registering - I wanted a technique that would "just work". I used to use OS X' FileSharing and the DropBox, but I don't get notified, and I have to mount the other user's Home DropBox by hand. Additionally the number of logged in users on OS X Client is limited.