The way I understand it is that learning a musical instrument is not a linear journey. In other words, you can't master one technique, and then another, and then another. You learn best by integrating "all" of the skills you are learning. As others have mentioned, we're all here to learn how to play music, not practice exercises. Learning some songs that include some of the skills you're working on is a great way to further develop those skills and apply them in different contexts. 

Keep rocking!