This quote by Arthur C. Clarke is very poignant to the story too:

Any sufficiently advanced technology is indistinguishable from magic.

The characters in the story (and we, the readers) think something supernatural and important is happening because we simply do not know what causes the Dome to appear. The reveal might be an anticlimax story wise (there's is no real big pay-off at the end) but when you take it in for a moment, it perfectly makes sense. Not everything happens for a reason, or: not everything that happens has a clearly defined meaning behind it. It's a human trait to seek more significance behind certain events because we sometimes cannot fathom that some things just happen. That's what I love about the novel the most, actually. The entire "community is isolated and goes to hell" has kinda been done to death (though it's still enjoyable in the way King writes his version), but the ending is what pays off the best, I think.