The practice is provided to decrease the tendency of boredom. Because if you only depend on chord strum and picking technique practice, usually you’ll get bored easily. However, if your chords movement is still not good enough, it is better for you not to stop practicing the technique because those two guitar lesson-materials have been arranged in a proper order. So when you find a song that match with the chord, you can directly play and sing it.
Usually in the process of guitar learning, many people like to skip the basic and prefer to play songs that become very popular on that time. Actually the music or songs, probably don’t match with their skill. You need to consider whether the songs are on your skill level or not. So it will be better for you to practice the material provided.