I've been watching a few videos to double check, as well, since for now I've been riding in the back seat with my newborn due to anxiety for positional asphyxiation. For head positioning pillows, there are different kinds so it's hard to tell why it may not be okay specifically but I guess for the blanket roll, the idea is that it's positioned with the whole body and not just the head. I've seen another video explaining that sometimes the head positioning pillow may be too thick or even fall down the back of the baby's head pushing the head more towards the chest, which can block their airway. I'm assuming that with a blanket roll, it's thick enough to not have that issue while also not being too thick to fall in front of the baby to block their breathing. I can see how the blanket roll can help keep the head positioned in the middle but I guess I'm still paranoid about the thought of the head falling forward so I'm still looking at more videos. Note: The headband thing to keep their head up is a no no as well.