Two questions here: “Why blood sacrifice?”and, “Why not just say?” In a word, the answer to both is existential.None of it makes any sense to me. Why did Gawd demand a death to "save" everybody? Way I understand it, Gawd made the rules, and Gawd can change the rules. So if Gawd wants folk to be saved, why don't he just say "OK, everybody's saved?"
Before God spoke everything into being, there was only spiritual reality. Since God spoke everything into being, matter exists. Now we’re dealing with a different reality.
The separation from God initiated in Eden was both spiritual and material. Lost personal relationship with God and dying flesh. God’s word repairs our spiritual alienation. God’s act of self-sacrifice in human form restores our once immortal bodies.
Make sense?