Some variable SF Symbols don't work.

Some SF Symbols (wifi for example) render fine with the variable. But many, mostly ones with the circle being variable, do not seem to work. The SF Symbols app shows them rendering with a variable fine. But in code it doesn't work. Am I missing something or is there a reason?

    var body: some View {
        HStack {
            Image(systemName: "01.circle", variableValue: 0.5)
            Image(systemName: "figure.wave.circle", variableValue: 0.5)
            Image(systemName: "wifi", variableValue: 0.5)
        }.font(.largeTitle)
        
    }
}