Never tried this version, but I have spent nights in both of these:
https://winterfetish.com/products/darlex-sleepsack and https://winterfetish.com/products/hooded-spandex-sleepsack.

As you cannot sleep on the side, because of the arms, the supporting mattress becomes important. A thin gym-mat made for a very bad night, but with a reasonable mattress, I had a fairly good night in the darlex version. And it is absolutely inescapable.
The hooded spandex version was more of a problem. During the night, when the muscle tonus relaxed, the spandex started to tighten the body in unusual ways and I woke up all the time because the shoulders started to hurt and the hood pulled the jaw into a strange position. Even when measured fairly tight, I eventually succeeded to escape from the spandex version.