You say,
The blood in and of itself has no intrinsic power or effect.
And yet you claim also that
The Mormon position is a biblically valid position.
It is not my argument. Here are the biblical teachings:
1 John 5:6
This is the one who came by water and blood–Jesus Christ. He did not come by water only, but by water and blood. And it is the Spirit who testifies, because the Spirit is the truth.
1 Peter 1:2
who have been chosen according to the foreknowledge of God the Father, through the sanctifying work of the Spirit, for obedience to Jesus Christ and sprinkling by his blood
Hebrews 12:24
to Jesus the mediator of a new covenant, and to the sprinkled blood that speaks a better word than the blood of Abel.
1 Corinthians 10:16
Is not the cup of thanksgiving for which we give thanks a participation in the blood of Christ? And is not the bread that we break a participation in the body of Christ?
1 Peter 1
18For you know that it was not with perishable things such as silver or gold that you were redeemed from the empty way of life handed down to you from your forefathers, 19but with the precious blood of Christ, a lamb without blemish or defect.
Matthew 23:35
And so upon you will come all the righteous blood that has been shed on earth, from the blood of righteous Abel to the blood of Zechariah son of Berekiah, whom you murdered between the temple and the altar.
John 19:34
Instead, one of the soldiers pierced Jesus' side with a spear, bringing a sudden flow of blood and water.
Hebrews 13:20
May the God of peace, who through the blood of the eternal covenant brought back from the dead our Lord Jesus, that great Shepherd of the sheep
Hebrews 10
18And where these have been forgiven, there is no longer any sacrifice for sin. 19Therefore, brothers, since we have confidence to enter the Most Holy Place by the blood of Jesus, 20by a new and living way opened for us through the curtain, that is, his body
Hebrews 13
11The high priest carries the blood of animals into the Most Holy Place as a sin offering, but the bodies are burned outside the camp. 12And so Jesus also suffered outside the city gate to make the people holy through his own blood. 13Let us, then, go to him outside the camp, bearing the disgrace he bore.
Here, here is the symbol; all else is literal, according to the Scriptures:
John 6:53
Jesus said to them, "I tell you the truth, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you."
May He cause His face to shine upon you and give you peace.