I forget where, but I read a blog post that described these sorts of things as controlled experiments - you want to test one part of your decision apparatus, not have it confounded by all the others.

Also, you are anthropomorphizing the paperclipper AI. It would accept your bargain, but demand not just a handful but as many paperclips as you could be arm-twisted into making - where your pain at the expense and effort is just below where you'd prefer the billion deaths. And then it would exploit your exhausted state to stab you in the back anyway. It's not psychopathic, it's just incrementing a number by expedient means. You can't negotiate with something that won't stay bought.