My take from this is that, in a long run, if unaided group would keep using their brains for tasks, they would develop their brain because of training, while AI group would eventually lose even their existing skills (at least when it comes to writing essays). Because if you don't use your brains, those connections on the brains wouldn't be needed either.
Every part of our body has a specific function. We are created in the image and likeness of GOD, so every part of our body has a purpose. Now, suppose you let AI replace what your mind or brain is intended to do.
In that case, you are betraying the purpose of the part of the body. If you let AI replace your brain's function, then it will become useless over time, and you are committing the sin of not honoring what the Lord has given to you.
AIs are a means to help the brain to maximize its function, and are never meant to replace it. We are better and superior to AI, but we can't utilize our full potential if we are AI-dependent.