Well, it's called Eurovision because it's run by the European Broadcasting Association, and any country that's a part of that association, even if they're not in Europe, can join. I mean, I do find it a bit lolworthy to have Australia there, and it's always worth a joke or two, but strictly speaking it's a private organization inviting its members, not some sort of public function.
As for the visual part, I'm not sure what you mean. I didn't watch this year, but those years I've watched there have always been a bunch of weird stage performances inbetween various more conventional ballad singers or whatever.
On another note, for a lot of people, I think it's simply traditional, it's comfortable, and I know a bunch of people either watch it as a family, or host watch parties. And then there's the competitive aspect of course. Which has always been political, it's inevitable.