God is the God of purpose,for everything He did has a purpose or reason, other than that He wouldn't have done it. There is a purpose of our existentiality on this earth. It wasn't by mistake that we exist on this earth.
"God created us to be doers of good works which God has before ordained that we should walk in them."[Bro. Eli]
God created animals,plants marine, sea, soil to sustain human life. So, when we ask the purpose of all these things are to support humankind to live as the Book of Genesis explains everything.
Genesis 1:29
"And God said, Behold, I have given you every herb bearing seed, which is upon the face of all the earth, and every tree, in the which is the fruit of a tree yielding seed; to you it shall be for meat."
screenshot from @mcgi.cares , Mass Indoctrination Teachings by Bro. Eli
So, if animals and herbs were created to serve the purpose for Humans so as Humans are created to serve God. We are created to learn the Bible to know the truth. We are created to do the good will and to share the love for others as God is love. God created us so that we can propagate his word throughout the world and many people would hear of Him from generation to generation.
Ephesians 2:10
"For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them."
So, the purpose of vine is to produce fruits. So any vine which fails to reproduce becomes useless. Since the farmer wouldn't be profitable from the vine. So, the farmer can decide to cut all the unproductive vines and burn. Then we ask, what about those humans who do not serve the purpose of God. But our God is always good to the extent that He wouldn't cut those people who don't serve His purpose. He has given all people time to repent and serve the purpose why they were brought on this Earth.
https://youtu.be/XxgAGPXlJTs