Arms need to be changed up constantly. Yes using a 10lb db won't do much for size agree. I don't see in this workout were 10lb is used.
Real arm growth comes from increasing tension in all the muscles. I like the look of denser muscles (myofibrillar hypertrophy not (sarcoplasmic hypertrophy) bolated soft look. It's not the weight used it's how you use the muscles lifting the weight. I'll continue to use this every 3rd arm workout. Hope this helps clear thing up, no disrespect with this answer. Thank you