Water or Antifreeze ?

[Crankster]

What is the supposed benefit of an engine coolant product that will not boil till 375° F?

The engine will have long been reduced to scrap well over a hundred degrees earlier.

Some sort of stop-leak product was/is often added by OEMs at the factory, and I assumed perhaps wrongly that antifreeze-coolant contained small amounts of stop leak as part of the additive package.