Why do angels have wings ? though they look like human beings ?
Wings helps them to fly from one place to another.
We the human beings use transportation like aeroplane, chopper, bus, train, taxi, etc to move from one place to another. It needs fuel. Fuel is purchased by money. We get money after completing our job. Earth is punishment area or place where nothing is free except the natural resources.
Angels are not beings of the Earth. Everything is free for them.