And in the meantime, it is openly disclosed so that others can learn from it and potentially it is available for licensing if it or later inventions based on it

And in the meantime, it is openly disclosed so that others can learn from it and potentially it is available for licensing if it or later inventions based on it are valuable enough. If you weren't going to do that, and you wanted to have a system that discouraged actually looking at what's already out there in case you infringed it knowingly, you might as well just let people file for anything but keep it secret for N years.