Most rooms share a circuit with more then itself. So say you are running your tank and its on a shared 20amp circuit. Your tank is pushing 12-15 amps. Someone comes and wants to vacuum and trips the breaker. Now your tank is out of power. I've also had workers come in and need power off in certain areas of the house. I tell them you can shut everything off except for the this one breaker which is dedicated to my tank. Those are the two big reasons. The third big one might be safety. You could put a GFCI breaker in the box instead of a normal one for added protection.