If flour seems to be accepted as sin offering/atonement, then why is blood needed?

>If you cannot afford two doves or two pigeons, you shall bring **two pounds of flour** as a sin offering. You shall not put any olive oil or any incense on it, because it is a sin offering, not a grain offering. You shall bring it to the priest, who will take a handful of it as a token that it has all been offered to the Lord, and he will burn it on the altar as a food offering. **It is an offering to take away sin.** In this way the priest shall offer the sacrifice for your sin, ***and you will be forgiven***. The rest of the flour belongs to the priest, just as in the case of a grain offering. — Leviticus 5:11‭–‬13 GNT If flour can be accepted, why did Jesus have to die for the wicked?