An idea to make interaction with design constants more natural

ExampleView.swift

struct ExampleView: View {
    var body: some View {
        VStack(spacing: .default) {
            HStack(spacing: .xl) {
                Text("Is this crazy?")
                    .font(.system(size: .lg, weight: .semibold))
            }
        }
    }
}

Font.swift

import SwiftUI

extension Font {
    enum Size: CGFloat {
        case xs = 12
        case sm = 14
        case `default` = 16
        case lg = 18
        case xl = 20
        case xl2 = 24
        case xl3 = 30
        case xl4 = 36
        case xl5 = 48
    }
}

extension Font {
    static func system(size: Size, weight: Font.Weight? = nil) -> Font {
        Font.system(size: size.rawValue, weight: weight)
    }
}

Spacing.swift

import SwiftUI

public enum Spacing: CGFloat {
    case xs = 4
    case sm = 8
    case `default` = 16
    case lg = 24
    case xl = 32
}

extension View {
    func padding(_ edges: Edge.Set = .all, _ spacing: Spacing) -> some View {
        self.padding(edges, spacing.rawValue)
    }
}

extension VStack {
    @inlinable init(alignment: HorizontalAlignment = .center, spacing: Spacing = Spacing.default, @ViewBuilder content: () -> Content) {
        self.init(alignment: alignment, spacing: spacing.rawValue, content: content)
    }
}

extension HStack {
    @inlinable init(alignment: VerticalAlignment = .center, spacing: Spacing = Spacing.default, @ViewBuilder content: () -> Content) {
        self.init(alignment: alignment, spacing: spacing.rawValue, content: content)
    }
}