I had a bad ID day yesterday. After posting my response, I saw another post on this same sea star and realized that I probably had the id wrong. I'm not sure what e. sentus eats. Maybe biofilm, I'm not sure anyone really knows.
I did a little research when considering these a while back for my own tank and was worried about my cleanup crew but also worried that it wouldn't get enough to eat - a common concern for sea stars other than brittles or serpents. In more recent threads, some people have reported having these guys for a year or more in established larger tanks, so you may be fine.
So I guess the bottom line is: please don't get nervous based what I said yesterday.