Angular en-AU locale not working for currency pipe

I'm adding the following code in my app.module in order to set en-AU locale as default:

import { registerLocaleData } from '@angular/common';
import localeAu from '@angular/common/locales/en-AU';

registerLocaleData(localeAu);

@NgModule({
  providers: [
    { provide: LOCALE_ID, useValue: 'en-AU' },
  ],
})

I've injected it into my component:

fee = 20.0

constructor(
  @Inject(LOCALE_ID) public locale: string) {

}

When I try to view the locale in my component:

<h1>Current locale: </h1>
<h1>Fee default: </h1>
<h1>Fee AUD: </h1>

I see the following:

Current locale: en-AU
Fee default: USD20.00
Fee AUD: $20.00

Why is the default fee not $20.00?

from Angular en-AU locale not working for currency pipe