Without patents: You are not provided any information, useful or otherwise. You can obtain this information any way you please, and use it. E.g.: reverse engineering.

With patents: You are provided with useless information. Information that is literally deliberately designed not to be useful. You can't practically speak use it. If you do obtain the information in any other way, you'll be sued into the ground. You'll be sued even if you've never seen the patent. You'll be sued even if your own invention is only vaguely similar. You'll just be sued, let's leave it at that.