The article doesn't say but it has piqued my interest in it. Is eshell of any usefulness? Can it be used to create scripts?

You can think of Eshell as a Unix shell that is 100% customizable, and those customizations are done in a very high level language like Elisp, not in C. Sometimes it's great to use macros in a shell script.

Yes, it can be used for running scripts: https://github.com/emk/eshell/blob/master/em-script.el