5 sets for a bodypart is not going to activate the muscle tissue sufficiently for any significant growth or shaping.
It's fine as a stretch and for cardio/practice, but it isn't the best use of your time.
I disagree with that. Some of the strongest men in the world don't do more than 2 or 3 sets per body part during most sessions. If you're body building and are focusing on definition that might be true, but for the rest of us there isn't any inherent reason to go beyond 3 sets most of the time.
The fitness program I use these days suggests only 3 sets before moving to the next harder exercise. In my experience, I've never had problems building muscle limiting myself to 3 sets and often times I've had problems with too much muscle gain too quickly and the strain that puts on the connective tissues.