You just never know. I do not think it is a matter of "if" only "when" an angel will pick at corals. They may not eat them, but they will nip at them causing the corals to not open fully. IMO, just not worth the risk in a reef.
Some people are like slinkies...they serve no real purpose yet can still bring a smile to your face when you push them down the stairs!:p
Have a great day! Brian