I like the Emacs text editor. For about 40 years I've used it for writing all non-trivial text. I can't imagine writing a LaTeX document without the features of the special Emacs mode I wrote for entering formatting commands and for running LaTeX and a document viewer. I'm using it to write this tutorial. Before the Toolbox was written, I was quite happy to write PlusCal algorithms with Emacs and run tools to debug them from the command line.
I don't like the Toolbox's text editor, and the interface the Toolbox provides is not great. But entering the code is an insignificant part of the effort of writing an algorithm. The Toolbox's features make running the tools and debugging an algorithm so much easier that I can't imagine giving them up because of an unsatisfactory editor or interface.
You don't have to use the Toolbox when writing your algorithms. There is a lightweight VSCode IDE that lacks some of the Toolbox's features. You can also run the tools from a command line. But there are good reasons to use the Toolbox for this tutorial. The Toolbox's features made it easier for me to write the tutorial and will make it easier for you to follow it.