On the Day of Atonement, the blood was sprinkled on this mercy seat to cover the tables of Law within the ark. God did not look at the broken Law; He saw the blood. Christ is our “mercy seat” (“propitiation” in 1 John 2:2; Rom. 3:25). But His blood does not just cover sin; it takes away sin.
No doubt many spiritual truths are wrapped up in these pieces of furniture, and all of them are of value. But the most important truth is this: all of this was symbolism and not the spiritual reality. It was this fact that made the tabernacle of the Old Covenant inferior.