I would have to say that the names and entire sentence was structured to set up a series of patterns that would be useful for future generations. In the story of cain and Abel it’s not actually clear at that point that blood forgives sins. That’s something we learn later on and attach to it. But what the verse does clearly teach is that Spear murdered Vapor out of wickedness.
That each story in the Old Testament has a theological intent is pretty clear. After all we know that there were innumerable stories that could have been recorded other than the ones that were so we must pay attention to the overarching theological truth that would be a message to all mankind profitable for doctrine and personal application.
In this case I see the division of the godly and the ungodly societies of men at their origins and the law of first reference is a foundational revelation of the heart of the issue. Literally, the heart of man.
We see the beginning of a city built by Cain named after his son Enosh (human) and their focus on this life only with the inventions of things pertaining to this world and its pleasures and ambitions. There are mentions of the daughters who were lovely, and pleasant, and beautiful, when there is no mention of daughters in Seths lineage though we know he had them this is to point out that these daughters in Cains camp were who is being reference later when the sons of God in Seths Camp start falling away by marrying them and leaving off their faith and expectation of a coming judge who will execute judgment on ungodly sinners. (Enoch's Prophecy).
This division of the Sons of Darkness and the Sons of Light starts here with Cain and Abel. There will always be a division between light and darkness and those who are Horizontally Minded (this life only) and those who are Vertically Minded (heart set on the Kingdom to Come.)
There is much more theology in these first few chapters that can be traced throughout the rest of the Bible and it is a case in point where knowledge of the rest of the bible is required to see the underlying message.