This is a fun read for novices who are interested in infosec stuff. I wish infosec tutorials/articles pushed writing custom tools. I've always considered password spraying to really be just taking super common passwords and flipping them around a bit. or . Instead of pushing some existing tools, I wish this article encouraged writing custom wordlist generators using common knowledge/sense.
What you say is the article lacks depth of what you find important.
You could easily make such with a few UNIX tools such as date and seq plus a few variables in your favorite language. So that is covered in Linux, Bash, and Python courses.
Burp also has support to prepend or append characters. They could've covered that as it is rather powerful. They could've also covered grabbing pastes from dark web to use as input.