Sassy Deluxe Sleep Positioner?

My daughter is 5 weeks and has acid reflux so she only sleep in her bouncer, carseat, or swim because they're elevated. She'll only sleep in her bassinet with a pillow under her. I've had this sleep positioner, but just remembered it today. I'd put it in a closet because I'd heard all these awful reviews. But now that I look at it, I don't see it harming her. It's got wedges holding her in place while she lays on her back, and the back elevates her. I laid her on it and for the first time she went right to sleep and stayed asleep. I just wanted some opinions. Am I putting her in massive amounts of danger? This is the first time she's actually getting rest and being on her back like doctors recommend at the same time. No links or nasty comments please- I'm just a curious first time mom!