If I squint I can kind of see how viewing the body might provide closure of a sort but there's no food or drink or readings or even music. It's just grim.

Let's plasticize our loved one so they look uncanny and unfamiliar and then stand around for hours in uncomfortable shoes! That's what grief needs!

And "grim" is distinct from "somber" or "solomn," both of which I think are totally appropriate vibes. We get that at the funeral. The wake is extra.