Why is CGRect.maxY at the bottom. of the CGRect instead of the top?

x = 0 is on the left side as I would expect it to be, but y = 0 is at the top which seems very unnatural to me.

For example, this code would define a Shape with a single path going from the top left corner to the bottom right corner, not from the bottom left corner to the top right corner as I would expect.

struct XEqualsY: Shape {
    func path(in rect: CGRect) -> Path {
        var path = Path()

        path.move(to: CGPoint(x: rect.minX, y: rect.minY))
        path.addLine(to: CGPoint(x: rect.maxX, y: rect.maxY))

        return path
    }
}

Are you saying "helpfully" sarcistically, or is that actually a helpful feature?

Because it just seems like it makes things a little bit more confusing for me right now. But maybe I just don't understand the wider scope of what that means, or why it is helpful yet.

I personally find it helpful because I find y0 being in the top left more intuitive. It's reminiscent of graphics programs that tend to default the origin point to the top left of the document, so I find it much more useful when laying out UI to picture it the same way. Also, reading in most (all?) languages starts at the top of a page and in English (which is my native tongue) at the left, so that's more natural to me.

And when working with UI components like scroll views or text boxes, top left is more in line with how we think of them as users. (Or, at least, top is; I suppose to people whose native language is RTL, the left part of top left might still seem a bit weird.) Mathematically, it may not be correct for the coordinate system to go from top left to bottom right, but I think in terms of UI, it definitely is better to do it that way.