Iodine free salt does matter in some applications, like pickling.

Also for some things you want coarser salt, which doesn't really have anything to do with iodine but most of that is going to be iodine free.

For general table salt and such though, yeah, doesn't matter.

And for gluten-free stuff, in some cases, the macros might just be better for your dietary needs/goals. My wife has occasionally gotten gluten free stuff because of that, not because of any issue with gluten.