WKWebView Payment Request API support in macOS?

When loading the Apple Pay demo page or the WebKit blog's demo page in an out-of-the-box WKWebView, both pages claim the browser does not support Apple Pay.

Does this really not work at all on macOS, or is there something environmentally that I'm missing?

As the last page notes, Apple Pay / Payment Request API support was explicitly added in iOS 13.

WKWebView Payment Request API support in macOS?
 
 
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