AI is good at writing small-ish tools from scratch. Most software development isn't like that, and people claiming it is are disingenuous. That being said, it is also true that if you are doing that kind of software development, AI will be very useful to you in the same way someone writing the code for you would be. It works, yay, you don't fully understand it, boo, but it still works. Maintaining it will be more difficult and error-prone, but it'll actually get you to build something, which is great!
That's a very tall claim, and one that I personally doubt. When it comes to refactoring old code with unclear requirements and inconsistent style, I have not seen AI do well. Of course, these things are bad, but that's the reality of most code out there - maybe you're lucky enough that you don't have to wade through that stuff.