[Baalz]

Yeah, the blood bless is really good at two points.

1 - when your units strength + weapon damage = (more or less) the defenders protection, and both are fairly high. Say, a jaguar warriors with an obsidian sword against Ulmish infantry. +4 damage is really significant when you're hitting for 0-2 damage. A fire bless on the other hand is just doing 6 + DRN damage against 10 + DRN protection, so it doesn't land that often.

2 - when the extra damage puts you over the point of being likely to kill the defender in one hit. Say, a Lanka Palashanka vs heavy infantry with a 12 protection buffed with legions of steel to 16. Again, a fire bless is not going to do too much, but the blood blessing makes it fairly likely that the main hit will do 26+ damage, outright killing the human infantry.