That same stuff can all still happen tot he lawyer who uses these tools. If he makes an egregious enough mistake, he's liable.

And that's why you want him to have to disclose that he used those tools.

Why do the tools matters? He is equally liable if he makes the mistakes without them.

So that you know he is more likely to make a mistake. Just like why many people avoid software written by LLMs, because it is much more likely to have bugs.