Good thread.
I don't typically depend on controller automation which can send a convenient alert when the temperature is out of range but can't tell when a pump has stopped pushing water.
For me, it's the same reason I observe and casually check my systems every time I walk by. I check that the animals look right, that the water is moving at the right speed in the right direction, that the stick-on thermometer on the corner of the tank is reading the right temperature, etc., etc..
Aloha,
Mark