I have had countless discussions (ok, arguments) with people who believe in the literal Biblical story of Creation, the talking Satan snake, and the flood that Noah endured.
They think that Evolutionary theory is a hoax and it's basically impossible to even get them to look carefully at convincing evidence like the fossil record, arctic ice samples, evolutionary history in DNA, or anything else that might point against their belief in the Creation myth.
I think that it's a weakness of the modern Westerner to disregard the depth of religious belief in fanatics.
Angels are like God's build tools. They are there. They may have a critical role but you don't have to understand them deeply or know too much about the intricate details to be a Christian or believe in God.
Still, there is quite the leap from one being to the other. I believe gravity is real, and its also a faith. There are different degrees of faith required for different elements.
More things point to God than to an Angel, since you could attribute existence or nature to something bigger. Where do angels actually fit there, the only thing to point to it is the bible.
I've asked my dad this before (Catholic), and his response was (paraphrasing):
Of course those stories are parables. There wasn't really a literal burning bush. But, whether the supernatural stuff is real, that's what faith is. Faith means that even when you can't see it, you know it's there because you can feel it. So you trust that what's there is what you think is there.
That's the supernatural parts of religion to my dad (I think he was in his 60s when I asked him about that.)
I am ashamed to admit that I didn't realize until I was well after 25 that followers of the faith, some of them, really believed in such beings and that priests of the Christian faith have to at least pretend to do so as well.
I was raised catholic(I'm agnostic) and I always took "Adam and Eve" and Angels as tales and alegories, elements to tell a story.