Copyright offers the most important protection software can have. If you want the result, you have to do the work again. Unlike patents that close off entire avenues of advancement just for being the first to add "with a computer" or "on the interwebs" to the end of some obvious activity, copyright acknowledges that you can do just about anything with a general purpose computer but if you want to do it, you've got to put in the effort yourself or pay someone who has.
Copyrights make you write your own code. Patents prevent you from writing your own code.