Main idea is described in more detail in the article Combining custom annotations for securing methods with Spring Security on my blog.

Of course, this is something you can live without but in my opinion it could help readibility and maintainability of the result code. There are few blocks you have to overcome if you want to combine several annotations with security rules on single method though. If you use Spring Security library for such purpose I'd be happy to discuss your view on the matter in commentaries of the article or Spring Security issue I've created to share my idea with the library authors.