I tend to run water wetter and regular water in my Nissan. If you break down on the track, that is easier to clean up. Track prefer that over radiator fluid. There is certainly a market for it. If I remember correctly it's good to use the water wetter in your water only cooling system because it has anti corrosion in it as well. How pertinent any of that stuff is up for debate, but again, it does serve a purpose.

Wouldn't the fuel filter catch a lot of that stuff?

I understand your point; I personally wouldn't run it.