In my experience you can achieve a lot with FaaS - but you still need an API, database and storage - which Netlify Functions doesn’t offer out of the box. I have a couple of sites deployed on Netlify with a ‘serverless’ backend deployed to AWS separately.
I’ve read this series twice whilst learning Javascript, once towards the start and again more recently. As others are saying, the lessons had a much greater impact after having some proper experience with the language.
The author, Kyle Simpson, has some really good video courses available online as well. He goes further in depth about some of the more interesting topics in YDKJS and is really able to sell some of his patterns.
Again, Kyle’s material was better digested after some practical experience with the language.