I can't get anyone to answer this honest question. All I get back is because the Bible says so. But there must be a reason for it. What is it? Here I will give you a reason why he had to be a man.
Romans says a man (Adam) caused sin to enter into the world, and also that a man would have to redeem it from sin. Romans 5:15 says “For if many died through one man’s trespass, much more have the grace of God and the free gift by the grace of that one man Jesus Christ abounded for many.” The Bible specifically says that a man must do it. The book of Corinthians makes the same point Romans does when it says “For since by a man came death, by a man also came the resurrection of the dead” (1 Corinthians 15:21).
Now it's your turn. Anyone?
You question is odd to me, "what benefit does it produce to make Jesus God?" Actually it's a complex question, a logical fallacy. We don't "make Jesus God". No one "makes Him" God, or "makes Him" not God. Either He is or He isn't, and it's just that way.
But you are looking for an human understanding of why this is somehow the right way? You complain when others say, "the Bible says He is God", but in truth, that's what matters, whether the Bible says He is God or not, and only then would we be able to go on to a spiritual understanding of how this works together with all the rest of what God is and has been doing.
Let's go to the two passages you've pointed to.
Romans 5:11-14 YLT
11) And not only so , but we are also boasting in God, through our Lord Jesus Christ, through whom now we did receive the reconciliation;
12) because of this, even as through one man the sin did enter into the world, and through the sin the death; and thus to all men the death did pass through, for that all did sin;
13) for till law sin was in the world: and sin is not reckoned when there is not law;
14) but the death did reign from Adam till Moses, even upon those not having sinned in the likeness of Adam's transgression, who is a type of him who is coming.
All men died because all men sinned. How is it that Jesus did not sin? How is it that death did not pass to Jesus as it did to all others? If He was a man from the ancestry of Adam, how is it that He did not inherit the curse of sin and death as did all others? But if Jesus came "in the likeness of sinful flesh", yet a new Man, He is apart from that. But even so, why God?
1 Corinthians 15:45-49 KJV
45) And so it is written, The first man Adam was made a living soul; the last Adam was made a quickening spirit.
46) Howbeit that was not first which is spiritual, but that which is natural; and afterward that which is spiritual.
47) The first man is of the earth, earthy: the second man is the Lord from heaven.
48) As is the earthy, such are they also that are earthy: and as is the heavenly, such are they also that are heavenly.
49) And as we have borne the image of the earthy, we shall also bear the image of the heavenly.
The two Men are different. One is of the earth, earthy. One is the Lord from Heaven. As we've born the image of the earthy man, we will also bear the image of the Lord from heaven.
A very significant point to make is that while the first Adam was made "a living soul", the Last Adam was made "a quickening Spirit", that is, "a Spirit that makes alive". Jesus, our Creator God, has the power to make us alive. Adam made us dead, but Jesus makes us alive, because He is the Lord from heaven, Who gave us life in the first place.
Much love!