In reply to Weston Ruter.

Weston,

You are the person who told me on this site a couple of years ago that the Customizer was still a work in progress, and shouldn't be criticized too much. And yet it remains clumsy, brittle, and the width of a cellphone screen.

So let's look at what is actually said in the thread to which I linked. John Blackbourne comments that Gutenberg works in such a way that "almost completely eliminates the ability to interact with blocks beyond the block editor." While Andrew Duthie concedes the point and reminds everyone that "for better and worse, we settled on HTML as the ultimate source of truth."

It is, of course, for worse. If Gutenberg were really being designed to make things work seamlessly together, it wouldn't be relying on HTML comments.