because you don't want to come home with your house burned down... that's why.
however unlikely that is, it just needs to happen once.
also sounds like a huge waste of energy... what are you doing that you need it to run 24/7? Seeding Torrents? Folding @ Home?
important enough to risk it?
electrical fires can happen anytime anywhere, unless you got a automated fire suppression system or someone stays at home... turn that stuff off.