I don't know this particular Brookstone machine, but I've had a sound generator for 6 years that does help me to sleep. The reason I need one in my case is very bad tinnitus (aka ringing in the ears, which is actually a tone), caused by repeated head trauma.
The sound generator helps to mask the tinnitus with a louder and more soothing sound. It has over 20 different sounds, but the one I almost always use is called Night Woods, which simulates the summer camping I love.
Nearly half the other sounds involved some kind of water, like waves at the shore, mountain brook, waterfall, rain, and oddly, thunderstorm. I use none of them because I fear they'll make me wet the bed in my sleep, or at least want to keep waking up to use the bathroom all night.
Another strange one is City Streets, that mimics traffic sounds like car horns and passing vehicles. I suppose it's for big city folks who might go insane in a quieter environment if they should move away.
Another funny one is Locomotive, which has the relentless and rather fast CHUG-chug-chug-chug, CHUG-chug-chug-chug, etc, of a steam engine. I can't imagine who that would appeal to, and how that could help anyone to sleep. My partner and I tried it once at high volume while making love, sorta like using a metronome, and nearly broke the bed frame.