Yeah that's a "how to use it in the simple case", that's not a "here is how this shit works under the hood so you can use it for more than just running userland

Yeah that's a "how to use it in the simple case", that's not a "here is how this shit works under the hood so you can use it for more than just running userland processes" and it also doesn't state the limitations (e.g. what instructions are supported and which are not).