Thanks for the article!
What I am missing in the article is a seperation between what the JAM stack defines and its best practises.
Git and the JAM stack happen to work nicely together, but there is no direct connection. You do not HAVE to use Git, you just should. Note that you can and should(!) use Git on the MEAN and LAMP stack too.
Setting up a CDN on the JAM stack is easy but not required. It MIGHT improve speed, but that is mainly dependent on the location of your origin server and your visitors physical location.
The modern software cycle with CI/CD is also not JAM stack related. Again… it is easy to set up for JAM stack sites, but CI/CD can also be used in MEAN or LAMP stacks.
I feel this article can improve immensly by starting with what defines the JAM stack (and what not). After that you can explain a little about best practises and why these best practises are so easy to set up, compared to the other stacks. This also automatically provides the reader with some extra advantages of using the JAM stack.