Why do some ppl put loose powder under their eye when putting on eyeshadow?

I was watching videos on how to put on all kinds of different color eyeshadow and in some of the videos the girls would put loose powder under their eye while they was applying the eyeshadow and then rub it in when they was done.Why do some ppl put loose powder under their eye when putting on eyeshadow?
It helps from getting shadow below your eyes. Usually, when they're finished, it dusts off easily, so the shadow doesn't smear all dark below your eye. Sometimes, they also use tape to pick up any powder left.Why do some ppl put loose powder under their eye when putting on eyeshadow?
they put loose powder underneath their eye because when you apply eyeshadow, sometimes the eyeshadow sprinkles underneath your eye so it would look like you have dark circles under your eye. so after you apply your eyeshadow you just wipe off the loos powder and so then you wont have eyeshadow all over your face. =) lol
Basically when you apply eye shadow, some of it could fall onto your cheek/under eye. And you don't want that! So the loose powder is a guard. After applying the eye shadow, you just sweep away the excess powder, and all those nasty flakes that fell will be gone. It really works - I do it all the time!
By putting loose powder under the eye you can easily get rid of any fallout from the eyeshadow.
the powder basically absorbs the eye shadow; so when you wipe it off; theres no shadow on ur skin/ under eye!
it catches the product that falls and is brushed off later for a clean finish. (it doesnt work with every powder for example baby powder)
so when you put your shadows on the little parts that fall on your face they fallon your powder instead making it easier to kepp or apply face stuff after wards.
It keeps the eye shadow from getting on the skin there.
I have never heard of that.