The word simple jumps on me as a semantically unpractical word. Simple can mean direct, as well as short. PG refers to simple as direct, i would argue. Especially when you read the last words of this text, when he talks about editing a draft. He describes how he achieves simplicity in his writing. That's the most important aspect of this text.
On the first glance i really like that approach, but i have the feeling that something is missing. They address the issue, that different people can be on different stages in different axes, but there is no real explanation of how to handle the differences. Someone can come in with little knowledge about the technology, hence not using it before but is very well suited to "lead" discussions about architecture or processes.
when i understood it correct it will enable you to use typescript-ish language features in standard node projects without a compilation step. which is pretty cool for small to medium size projects