Not to mention fire safety.
The only thing that stays on here is the fridge.
Your fridge is actually more of a fire hazard. Your fridge has a compressor that kicks in to keep the temp constant. That compressor has moving parts in it. Just for sake of supposin', let's say that compressor has a bearing in it that seizes and the motor keeps trying to turn it. The causes friction. Friction causes heat. Heat causes fire.
Inside a computer there are thermal shutdown protection mechanisms that will shut the computer off if it exceeds a specific threshold. I have had computers running 24/7 since the middle 80s. If I haven't had a fire yet I won't likely have one now. Not caused that THAT anyway.
Maybe from my fridge....
I know the fridge is a fire hazard, but for obvious reasons I can't turn it off, else I would do it.
I have had experience of a fire in an electric shower, while a member of my family was using it, so you might understand where I am coming from.
But six computers on all night, plus all the attached devices and maybe tv's on standby probably eat up 5-10 dollars a month in electricity I would guess, but then its you who is paying the bill, not me.
Still think its a fire hazard, but as you say, you feel safe so I guess that is ok for you.