Remember, it is a contract. It only looks like English language.
I don't have a full copy of the EULA, but in another article they state that "Work" is "any book or other work you generate using this software". They are talking about the output of the program, they are not restricting your original content.
So, if you want to sell a PDF of your book through other channels, you better not make the PDF with this software. Use the "Print to PDF" popup in your regular software or something.
Oh, of course. The discussion is about the output of this program, though. If you format your book with it, you lose all the formatting if you want to publish on other channels, as the article said.
> if your Work is provided for a fee (including as part of any subscription-based product or service), you may only distribute the Work through Apple
What do you base your interpretation on?