If the holder is inflicted with confusion, then they are instantly cured. One-time use.
Signal Beam is everywhere and it's infuriating 10% of the time, but not infuriating enough to dedicate your item slot to Persim. You can always use this alongside Shadow Dance, but one of the users has Own Tempo and you miss out being able to use Special Bloomers to hit harder and switching out of confusion. If you're going to boost and use Shadow Dance though, this may work out for you.