I have never seen a mechanical pump "just go". They'll start to seep long before something really bad happens. An electrical component will usually just quit. No thanks. I don't see any upside to an electric waterpump on a street car.
I've seen mechanical pumps lock up, shear the shaft, launch the fan clutch, blade, and shaft segment through radiator, hood, and oil pan.
I've seen em start peeing after no use at all, sitting stil in the driveway.
I've seen mechanical pumps shear shafts and let the impeller free, with no notice, warning, or indication.
Ive seen impeller assemblies break free, and not turn.
Ive seen impeller segments break off and imbed themselves in pump bodies, locking pumps.
Limited exposure and internet hearsay, are not good reasons to recomend or not recomend a device. Many new cars, GM line in particular, are comming from the factory with not only electic fans, but electric water pumps, and because of the shut down at idle fuel savings, also electric air compressors for AC.
Worlds come a long way in the last 30 years, and I know the favorite montra on here is put a carb on it, and return your car to the 60s. Truth be told, some poeple like leaning forward.