Hey, Beranga.
My apologies on the unusually long delay in responding to your comment. It’s been a wild two weeks! I’m glad that you’re enjoying the book. I had a lot of fun with it. 
To answer your question: yes, pretty much that’s what’s happening. There are other ways to achieve the same—or at least a similar outcome—but this is the way Apple recommends you handle tile maps and physics, and it works really well, too. 
Hope that helps!