confused mama about halo sleep sack

I bought some today cuz my lo rolled from tummy to back the other week and it says it's a wearable blanket and you can transition him out of being swaddled.. but it also says to not swaddle if he's breaking out of it and/or showing signs of rolling... so is it not safe to use? Or do I swaddle him with his arms out like it suggests? Confused mama over here.... no idea what to do