Blanket advice like this is misguided and implies that every writing situation is the same.
Grog McGraw

Your point on the tense of verbs is a good one. As is the case that, like salt, sometimes tense isn’t important and sometimes it is critical.

What is the difference though, between a single lengthy sentence, which holds a complex idea and a paragraph composed of short sentences which holds the same idea, if not the same words?