Dying is Magic shorthand for leaves the battlefield and enters the graveyard. When you sacrifice a creature, that creature often dies , which is why you can use Blood Artist and the like with your sacrifice outlets
All creatures they control are goaded
You want to build your deck in such a way that you always reveal a Human when you cast this card, and ideally, so that you have choices and can take a good one for the situation
Halfdane - D+ While I'm not super stoked with Halfdane's ability of copying power and toughness, I do like the idea of bulding a clone deck around him where all you do is take power and toughness from other creatures
Basically, if you miss out, its not a huge loss
They might show up in certain budget or niche strategies that want immediate mana ramp