If the tank rusts and breaks, it’s not going to hurt the attic, since the piping to the house will still be intact. On the other hand, if you have a water heater break every eight years, you should be following the advice on this site — changing anodes and controlling sediment buildup — so that that doesn’t happen.
Of course, you could still replace this tank and just happen to get a defective one — what they call a “leaker” in the industry — and all the anodes in the world won’t save you from that. But Undee70ss’ advice would protect you there.
I expect that right now your heater is centrally enough located that you don’t need a recirc pump and being inside, will probably lose less heat to an unheated space. And recirc pumps mean hot water is flowing all the time and radiating away heat all the time.
So I vote for staying put. But if you do move it, get a demand-type pump instead of a recirc pump. With that, you press a button under the sink and have hot water within a minute. It doesn’t circulate continuously. And have the plumber insulate all the lines.