Percolation? Heat soak? Don't drive during summer??

I think that's a little dangerous. How many people have had engine blocks or heads crack because that plain water froze? Yeah, maybe where you live it won't ever get that cold. But freakish stuff happens all the time.
I think he's just pointing out the difference between Water and anti freeze cooling.
Nothing mention about running distilled water, although the OP possibly could considering his climate.
My reference was for our drag car recipe.