Dead rock being the operative words here. Not all divers (even some experienced ones) seem to understand what those are. The guy I dive with has had to have a word or two with supposedly experienced people who claimed they knew the difference. They didn't. Jamming them into coral, sponges, etc. etc. Don't assume you will be allowed to use these automatically in the Marine Park or that the DM won't tell you to put them away if you use them inappropriately. I think too often they are a substitute for good buoyancy control.
I learnt this trick from the DM himself. He also used it to point the little critters, which often I didn't see them until they moved.
I have used it for 12 years in many places, including marine parks, such as Komodo, Raja Ampat, Cabo Pulmo, Galápagos, Bunaken, Lembeh, Wakatobi, GBR, etc. and haven't, yet, been disallowed to use it (knock on wood).
Only idiots would use it to jam it into the coral, sponges. I haven't seen those guys around, thank goodness.
It's much better than sticking your finger onto the dead rock & having your hand got brushed over by waving hydroids as the current sweeping over your hand, as gloves are not allowed in some of these marine parks.
The pointer helps your hand elevated high enough above the hydroids from touching your bare hand. Sometimes the only accessible view is between the hydroids like this blue-ringed octopus and yellow-mask angelfish, below.
Another trick that I learnt from underwater photographer is to shoot at low position or at least level with the object, with ocean blue background, if possible (often is not possible, so you take what you get). So, when you lower your head down, you need to be aware of your surrounding. You don't want your face got whipped by that dang hydroids.