A lot of people do leave dishwasher machines going through the night to wash the dishes and it's reasonably safe.
However I remember reading back in 2013 about someone dying in their home or apartment when a dishwasher caught on fire while running overnight.
So I personally would not leave the dishwasher running overnight or while away from home.
Also one day I was home and using a dishwasher and it flooded the house because the water valve would not shut off so that would be one reason I wouldn't want to leave the dishwasher running overnight or while gone away from home.
If you need to go to sleep and the dishwasher is in mid cycle just shut the dishwasher off and turn it back on in the morning when you get up to be safe.