Speculation: The production of this page was likely handled by Marketing, which functionally likely sits in a different org within FB and doesn't have access to many eng resources. So, Marketing sees WP VIP as an easy way to get a site up by just running a credit card. Speaking from experience, I think this "outsourcing" is probably good – if there's indeed no engineering team dedicated to Marketing needs like this.

That said, I'm sure WP VIP will break down when Marketing's needs increase – such as when Marketing needs to do internationalization, or perform a timed launch of a new site/content update.