When you want to point out something on your slide a laser pointer comes in quite handy. To stand out on the screen a green laser pointer is much better than a red laser pointer. However it is getting more and more difficult to buy a green laser pointer due to national or European safety regulations.
In addition having in one hand a wireless mouse and in the other hand a bulky laser pointer is quite inconvenient. Especially when the mouse clicks do not have the desired behavior.
You either don’t really care if anyone can see what you’re pointing at or you’re cheap and you use the free pointer you got from a vendor at the expo. Of course, you could be one of those considerate folks who buy very bright red pointers, because you stubbornly like what red looks like even though human eyes are not sensitive to 633 nm. That’s fine.