Well, as an experiment, look at how you could have stated that paragraph in a more simple manner. You could have probably gotten the message across with “Why bother learning new words? Simple is better, no?” But there’s a lot of nuance that would be lost.
A lot of vocabulary building feels more academic than useful, that’s true. But there’s another aspect to reading, which involves exercising your brain. That requires challenge, in a similar manner as you’d exercise muscles. And you could see general life improvements from challenging your brain constantly.
Reading 3 books at once is awesome. If I’m not in the mood for one of them I have 2 others to choose from, which means rather than skipping reading that day, I’m always reading.
But my TBR is just a shelf, where I pick up anything on a whim. No quotas allowed.