I could understand the term "clueless" if it was used meaning that, if you love the game (you want people to play it and provide thrilling battles) you shouldn't use that ability.
Unlike chaining someone, which doesn't cause a really harmfull impact, confuse is way more frustrating. I bought Syren and took her to 3 star just for Colosseum. I never use her in any other place and don't plan more promotions.
My approach to games I like is always the same: spread the illusion, do not kick people out.