Are blood packs good for anything?

Have a look at this quest:

http://fallout.wikia.com/wiki/Blood_Ties

Ah, so they can be sold or used for healing with a perk. Thanks.

Personally I just sell all blood packs as drinking blood is against nature. Being against the nature is being against humanity. And the Enclave doesn't approve of things that are against humanity

I like my Enclave with a hint of cinnamon, in a boil-in-blood-pack.