I believe what I see, and I am suspicious of everything written. That's why I don't like to post anything about livestock I have not seen first hand.
Personal experiences with many CBBs:
• I used to think Copperband Butterflies were hard to keep until I began to keep them. I've lost a few, but no more than any other fish.
• I've been keeping CBBs for years with clams and corals never had a problem. But I feed all my fish several times a day.
• Even my clients keep CBBs for years, feeding a blend of food I make for them (no big secret - it's just a seafood mix). And they feed NO Mysis (gasp!) But I highly recommend Mysis (as well as black mussel) for all Butterflies.
• I did have a CBB unable to keep up with Aiptasia growth in a client's 125 - but I put a Raccoon Butterfly in and the pesties were soon gone. I think some CBBs only eat tiny Aiptasia - or none at all. But that's rare, in my experience.
• The tanks here at the house have tons of 'pods, stars, snails, worms, tiny featherdusters and other critters, and both have Copperbands.
DISCLAIMER: I use refugiums in all personal tanks and all but one customer tank.