Answer:(these are all in my opinion and guesses because im not good in photography)
1. I think it makes it more peaceful, as you can see in with and without pictures.
2. WHen you go horizontal, you can see the bottom of the waterfall, where it's crashing into the water at the bottom and it's very pretty.
3. They can put lights around whatever they are taking a picture of to make it light up.
4. it can sometimes be way to dark.
Explanation: