Block heater + starting car

[Big Leegr]

So far, I haven't had any problems, but I've been told that you shouldn't start your car with the block heater still plugged in. The ones I've seen are basically a wire loop that you thread into the block. The loop gets hot when plugged in, the oil warms up. I don't see how this can damage anything. (I have a remote starter.)



Anyone with knowledge/experience of this ?