It's no extreme. It does work and there are also toys that generate white noise to help babies sleep. Also a lot of Spotify playlists dedicated to this.

They sell white noise and whale noise baby products, many parents started using their phones or Echo/Home devices. So yes, anything with a speaker will work, and is likely closer to what you hear in the womb then what one's mouth can simulate. It also still works on adults. I regularly have a fan or white noise going when I sleep.

Not an extreme. Pink noise works really well and brown noise to some extent. White noise is a bit harsh for our human ears.

The pink noise besides simulating the shushing also serves as sort of a noise blanket to make other sounds being made around the baby pop up less, sort of sound mantle.