I think this is a key part of Lucas's worldview, and it explains some of the Special Edition changes. Lucas believes even the scary monsters should have a spark of life in them. They shouldn't be dull, dead things with no soul.
Notice how by giving the dianoga a blinking eye with a pupil, he infused it with some kind of a personality and a soul. Because it may want to eat the heroes, but it's not a demon from hell. It's really just an animal and the garbage masher is its home.
A lot of people understandably found the sarlacc scarier when it was just a gaping hole in the ground. But Lucas has said he didn't like that "[t]here wasn't anything alive about the whole thing." That's the whole explanation. The original sarlacc had no soul, no personality. It was a Lovecraftian horror. But the sarlacc is alive too. It's almost like a baby bird or pterodactyl, it's just hungry.
"Lord Generals Acetominophen and Ibuprofen have quelled the worst of the Ankle rebels, but they've gained sympathy in the Calves. Lady Celexa, Hand of the King, has earned her keep these past months, yet still I fear the mysterious workings of the Cult of the Gut."
Talking about my health issues like Robert Baratheon has proven very therapeutic
"I have an Ankle in open rebellion, there's unrest in the Belly, and the Nightmare King sends his raiding parties nightly; what would you have me do?"