High instability is kind of like simulating a temporal storm with a good chunk of the loot that entails, and temporal storms are fun. So, by placing down and powering a rust ward, you can stay at 0 stability without shredding yourself -- and your armor -- to fight drifters at your leisure. It might have a chance to prevent drifters spawning directly on top of you too, to add a bit more utility for temporal storms.
It doesn't actually ward off stability loss, so it's more for managing the consequences of being in a low stability area for a long time.
It might not even necessarily need to be its own item -- maybe just an upgrade for the existing rift ward. It's what inspired the idea, at any rate.