... is like saying "Wii-Fit doesn't make you fit, because you can just step on and off and the game thinks you are exercising".
If you do this, you are just fooling yourself.
Coverage means nothing unless you assume you are working in an environment where developers are writing good unit test. With this assumption, suddenly it becomes a great measure of how much of the code is untested! [or in BDD lingo.. how much of your code is not required to satisfy the current set of automated requirements indicating either a requirements gap or too much code!]