Funny thing about water and gasoline...
In the days before 10% ethanol, virtually any amount of water in the gas would drop to the bottom of the tank and sit there forever (if below the pickup). This may rust the tank but is less likely to damage the rest of the fuel system as long as there is a fuel filter to prevent rust flakes from making their way to delicate parts. One advantage of ethanol in your gas is that it acts as a co-solvent and will allow the fuel to absorb (and burn off) a modest amount of moisture. (Gas line antifreeze and "water-out" products are just alcohols that allow the water to dissolve in the fuel)
On the other hand, the presence of ethanol makes the fuel more hydrophilic so it has a greater tendency to absorb moisture from the air. Also, when the water hits the saturation point, what drops out (often during a decrease in ambient temperatures) makes a mess. A fairly large volume of a (sometimes) viscous emulsion can cause corrosion and gum up carbs/injectors/fuel pumps etc.; especially since the water is in suspension and no longer sitting on the bottom of the tank.
Ethanol is not our friend but isn't necessarily all bad if the original gas is pretty much water-free and you don't let it sit too long in the tank exposed to moist air.