I think a fundamental mistake you (and other commenters on this article) are making is judging the value of the "plain" English version by whether you think it's good writing.

However, the article's intention is to use plain language to be accessible to individuals with intellectual disabilities or other difficulties in language (i.e. recent immigrants).

As a fairly well-read and educated person, I also find the "plain" version dull and uninspiring. However, I accept that the article is trying to make the point that such writing may be more broadly understandable.

For example, I recently had some relatives immigrate from a non-English speaking country. I helped them set up internet and noticed there were multiple points during the company's signup and payment process their lack of English fluency created huge hurdles.