The flat seven of each chord often serves a specific purpose is often used to mark that the chord change is coming. So, if you play the one chord, just before going to the four chord, you can play the flat seven of the one chord, then that serves as a signal to the other musicians that now it's time to change chords. That's a good way to communicate. I will now play an example where I play just a root note in that riff. And then before going to the new chord at play the flat seven