Unique or commonplace? Do Christians put such central emphasis on the fact that Jesus sacrificed his life?

No when we sacrifice ourselves for others it may get us a few more days of protection from whatever but when GOD in all SPIRIT and flesh sacrificed his life it meant protection for all eternity. When the soldier stabbed him in the side this was a crucial moment because GODS blood had to unite with the earth and in doing so spread through out the entire universe. And when GOD gave up his life he was taking on all of sin that had ever been and all of sin that would ever be. So he felt all the cruel nasty evil things that man kind had done or would do to each other through out all of history. GOD says all sin that would ever be was covered. Jesus was the SPIRIT of GOD wrapped in flesh.