It was quite useful, I really only used it to figure out how many were armed (I learned everyone was after the second time). I relied more on glide kicks, so knowing their exact location didn't matter if I didn't have an open attack, to be honest. Indeed, Scarecrow was a big aspect of Asylum, I liked when you first saw him in the morgue. I didn't know who he was originally, so when he popped out of the body bag, I actually did jump. Avoiding him was also considerably fun.