Like any other decompression needle it was the correct gauge, and once necessary I will use it. I recommend it for when your body or someone else's has some trouble breathing. Just jab it in him in his lungs and that should let out all the pressure that's built up guaranteed. Joking aside, It's a useful tool for fluid buildup in the lungs and around the outside, specifically blood. It might help with a collapsed lung, but I haven't tried that or had that happen anytime around me, and it's not what it was built for.
Get one even if you don't know how to use it. Learn how to use it. Even if you've never used it real world out side of practice there could be a situation someone needs one jab in their lungs, and there is a medic around that needs that tool. You can help provide it.