not sure if you have been playing long but almost every single mission has a section where you are swarmed with some sort of mob and this right here is a mob destroyer.. dinklebot will have you stand in one spot while wave after wave come after you and this helm will make him hack faster lol. also in both VOG and Crota there are plenty of mob waves that this thing will help you obliterate.

This helmet comes in handy anywhere...if you haven't noticed most mobs are in groups/waves/etc

This is warlock...