Resistance training enables the body to experience a higher load in a targeted muscle-group way. As a result the adaptive response this elicits leads to greater strength and larger muscle size. Which means that Buff is a difficulty Level 5 workout and not suitable if you're new to all this. For everyone else however this has to be that occasional workout you go to in order to test how far you've got on your fitness journey.
Extra Credit: Use 16lb+ (8kg+) dumbbells.