2How to craft it
when to throw one
The bounce is the whole point. A normal glowstick lands on the first thing it touches. This one keeps traveling, so it works its way down a shaft and around corners and lights the part of the cave you actually wanted to see.
That makes it the cheap way to check whether a drop is survivable before you commit to it. They also keep burning underwater, where a torch will not, so a stack in your hotbar solves flooded caves and the dark stretches under an ocean without any setup.