It's a long boss fight and you've just run out of mana, but you have this belt in your inventory along with some other int/mp items.

Feign death, switch this gear on (with a mod like outfitter).  Pop up with viper and autoshot until your FD cools down.  Feign, pop up and switch back to your DPS gear.

Or just shard the belt and next time you go OOM stand there and auto-shot/steady shot your way to lower dps.

Yes this item needs buffed (and probably will get it with 2.1) but most items have a use, you just have to have the creativity to figure out how to utilize them.