It’s the best presentation for this style of content that I’ve ever seen. Having a description of what’s going on with a particular code block, plus highlighting the relevant parts, and moving that highlight or swapping out specific parts of it as I go through the content made it much faster for me to grasp what was important and what changed between blocks than would have been the case if the author used traditional static sections of code. This isn’t documentation, it’s a follow-along tutorial, and for that purpose this presentation style is 100% appropriate.