Here is our understanding of the Copyright, viewed internationally:
-The Copyright represents the automatic right - the author's right - conferred upon the author over his creation, without formality.
-the copyright filing for a work (literary, artistic, musical) proves that one is indeed the author, which avoids those (many) cases in which it will not be possible to prove that one is the author, or to prove on what date a work was created (date certain and proof of anteriority are key to a suit for copying or plagiarism).
-Unless one must collect royalties from American copyright management companies, a copyright filing providing official and certain proof of the creation, paternity, copyright and anteriority of that copyright, the filing is valid in all countries signatory (including the USA) to the Berne Convention and makes it possible to assert one's rights in all those countries.
-The Copyright is extremely valuable (to the extent it is accessible by a Copyright filing via the Internet) in Europe and the Americas.
-The Copyright must be filed as soon as the creation is completed.
-Each time the creation is modified (updated, amended), the filing must be done over again. This is so that the Copyright filing contains the most recent (and hence complete) elements of the work to be protected.