I don't think they are really decoupled from iOS. Updates are still delivered through iOS updates. I think it's in the App Store because when people remove it f

I don't think they are really decoupled from iOS. Updates are still delivered through iOS updates. I think it's in the App Store because when people remove it from their homescreen, the logical place they're going to search for it to bring it back would be searching in the App Store. But it's not an actual app delivered by the App Store, if that makes sense.