In my opinion, Iron X or product like it are important.
I'm always amazed at how contaminated paint can become. I've used Iron X on my truck and on my wife's SLK350. While it's hard to see the red bleeding effect on red paint, (by truck), I can still see it. My truck is parked outside 24 by 7 and I used Iron X every time I wash it and it always bleeds.
Make's me wonder....
What's in our air?
Same goes for the Mercedes. It's silver metallic and every time I wash it I mist some Iron X onto the horizontal surfaces and while I don't see a lot of bleeding it is present.
To me it makes more sense to chemically dissolve any iron contamination off the paint then to try to mechanically remove it using some other means.
My take....