muscle head

The idea of not gripping the bar has come from the guys who suffer with joint problems, if you have small wrists, that grip is great.
But be warned, you have no control on the bar, so be confident in your lifting before you try it.
you can also use the grip on curling, tricep push downs and also pull downs for the back.
Cardio..............well if you want size, which most guys want, then don't do it unless you are consuming enough protein to stop your body going into a catabolic state.

Good luck.