the idea is to get the bulk of your iodine in KI. its cheaper and can convert to I2 in the body. I2 definitely converts to the salt iodide in the body.
but the I2 is important, especially with all women and cancer patients. when the body is getting all the iodide it needs then the I2 is more available to help with things like cancer.
in any cancer situation i have to stand firm in my belief that a person should take as much iodine as they can tolerate. it cant kill ya, it aint chemo! but it damn sure wont work if you dont take enough, and thats the whole point.