I've used the Kent product, at 2-3 drops per 10G weekly, and it successfully prevented what appeared to be molting deaths in ghost shrimp; extending average lifespans in my tanks from mere weeks, to normal. Beyond that, my shrimp-keeping experience is limited.
Some say that my results are due to iodine killing harmful bacteria, but I've seen reference to iodine being used for this purpose in saltwater tanks, and the required dosage is hundreds of times higher. Even the recommended saltwater supplemental dosage is 20x higher.
Some say that shrimp can't utilize iodine in the water at all, so it has no effect. Or the tiny amount added to water is too small to have any effect, and is dwarfed by the amount of iodine in typical shrimp food. And that the recommendations to use it are just a ploy to sell iodine, though the cheap price and small dosages involved would hardly make it a worthwhile deception.
And many others say it increases molting frequency, as per a research paper I've long since forgotten the name of; and conclude this is an indicator of irritation and toxicity. To me, it seems unlikely that such a small amount is such a potent irritant; and that increased molting could just as easily be an indicator of better health and growth. But I've never seen anything in that paper or elsewhere that clearly supports either interpretation.
I wrote this off as more of a religious than scientific debate long ago. It probably isn't necessary, but probably won't hurt either. So it's probably best to try it if you're so inclined, and come to your own conclusions.