Why isn’t the dockatot safe?

I know they say a baby can sleep in it as long as you’re watching them, but my question is- why can’t they sleep in it during the night the first few months of life when they can’t roll over? I know it’s for suffocating reasons, but again.... if they cant roll over how would they suffocate?

I’m just curious! I don’t have a dockatot and was actually looking into getting the snuggle me, but just wanted to understand why. I know that dockatots are banned in other countries.