There are times I go out for runs or hikes or even walks but I don’t want to carry my backpack with bladder. I also don’t want to have to deal with carrying a water bottle. While you do carry this water bottle, it has a nifty grip that allows you to strap it to your hand so that you are holding it but not.
Confusing? Take a look:

The Camelbak Quick Grip allows you to slide your hand in between it and the water bottle. You tighten the strap and you can let the water bottle hang.  I love not having to hold onto the bottle, therefor my hand doesn’t cramp up.  It even has this nifty little pocket for stashing my keys and ID. 
For short trips I wish the bottle was a bit smaller but overall I love having it to use when I don’t want a backpack but want to bring water with me.