This passage describes in detail the armor of God. Whenever I read it, I remember the novel from the early 1990s entitled "This Present Darkness" by Frank Peretti. It was a book that had both angelic and demonic characters waging war against one another and how that war manifested itself in humanity. Whether or not we believe in angels or demons, the book was an interesting read.
I went through a period in my spiritual journey when I really wondered if demons existed and I looked for angels everywhere. It's a nice thing to believe in angels - to think we have some extra protection from the evil in the world, maybe a guardian angel that is 8 feet tall. I really don't know if any of that is real, but I have decided that whether or not angels and demons are real, it doesn't matter. What matters is God.
Paul starts out this passage by saying "Be strong in the Lord." The point isn't about some spiritual armor that some folks read literally. The point is really to be so focused in our lives on God that negative or evil influences can't really have any affect on us. If we are godly minded in all we do, if we make daily decisions to love God and love our neighbor, if we pray without ceasing, then our lives will be all the better for it. We will have the joy of the Lord in our hearts. We don't need to focus on evil or the war between good and evil. We need to keep our focus on God and our relationship with Him. That's really all that matters.