The Lord wanted salt with all of Israel’s grain offerings, but He did not want leaven or honey offered,

“No grain offering which you bring to the Lord shall be made with leaven, for you shall burn no leaven nor any honey in any offering to the Lord made by fire. As for the offering of the firstfruits, you shall offer them to the Lord, but they shall not be burned on the altar for a sweet aroma. And every offering of your grain offering you shall season with salt; you shall not allow the salt of the covenant of your God to be lacking from your grain offering. With all your offerings you shall offer salt” (Leviticus 2.11–13).

Why did He want one, but not the others? For that matter, why did He require many things, but not other things? He has desires of what He wants from His creatures, and things that He does not want from them, and it is our job to see that we do what He wants.