Point, Point, Point.

Yesterday, some one walked into the dive shop and and asked what's a pointer used for. I find it hard to come up with an answer because of the way I've seen people use pointers. 

No, pointers are not there for you to poke the puffer fishes (or any other sea creature!). 
No, you do not use pointers to poke at corals so that you don't crash into them. you are not even supposed to end up in that situation in the first place!
No, you don't use the pointer to touch things that you won't otherwise use your hand to touch.
No, you don't use pointers to flip over rocks to see what's hiding under the rocks.
No, you don't need a stick to "protect" yourself. A magic wand from the pages of harry potter belongs in fiction.
No, you don't need a pointer to secure yourself to the sea bed when the current is too strong. (If it's too strong, what's the point in fighting against it? Do a drift dive please!)

The only (weak) reasons i could give him is that:
1. they are used as tank bangers (to make noise)
2. they are used as measuring devices (marked pointers can be used to estimate small distances)
3. In the unlikely event that you really need to hold your position on a SANDY BOTTOM, then u can stick it in. Then again, it is NOT Recommended.

You don't bring a stick when u visit the zoo, do you? so why bring it to poke around when diving?

Having said that.. a pointer is just a tool. it's usefulness depends on the user. So i don't blame the tool, I blame users who abuse the tool! hahah. Repent now u evil anyhow-poke-here-and-there-for-fun pointer user! =p