Another good reason (besides being a very good looking animal) - the Nardoa series starfish reportedly eat asterina's ---- something very attractive to those of us plagued with those little buggers...
Problem is, what are they going to eat when all the asterina's are gone?
If you find, would be very interested in hearing how it fits in with the rest of your tank population.
Nardoa and Asterina spp Sea Stars
There is some controversy over the Asterina species sea stars, which can multiply to great numbers in reef aquariums. Most aquarists report no problems with them, but some claim that they eat SPS corals and make every effort to remove them. There are more than one species of Asterina and it's speculated that some species may be harmful. It's also speculated that the Asterina sea stars will consume SPS corals once they reach a certain density. I happened to put a Nardoa species sea star into a small reef aquarium that contains a large population of Asterina sea stars. I discovered that the Nardoa sea star regularly consumed the Asterina sea stars. The Nardoa sea star san be a good biological control for those aquarists that want to reduce their population of Asterina sea stars.
PS: My LFS has them pretty regularly, so they cannot be all that hard to get.
echinoderm hunt 
