Sending a photo to a friend in the next room or between your devices is not a problem; any instant messenger or local network will suffice for this. But transferring a really large file to a person in another city, and without it ending up somewhere on someone else’s server, is a much less trivial task. Usually it all comes down to the same scenario: upload a file to the cloud, wait for it to download, send a link, and the recipient has to wait again until the file is downloaded from him.