> By making translation units as small and simple as possible, translations become easier and are less likely to be left untranslated.
Have you measured it? Are pages where you did this split actually more likely to have more translations?
> Moreover, simplifying variable names increases the likelihood of hitting the translation memory, thereby making the translation process more efficient.
It's not significant. Sentences within paragraphs of body text are not likely to be in translation memory anyway.
Making translation units shorter is generally a good idea, but the way in which you do it is not great. It adds a lot of markup, which makes the page hard to edit.
It's better to make the paragraphs shorter and rely on the Translate extension's capability to mark each paragraph for translation.