This is an easy question to answer for anyone like myself who actually enjoys reading Shakespeare. Once you've read all that is available, it would be amazing to have more. Whether it was written by Shakespeare himself or AI, is irrelevant once the AI gets to the point where it can do the same thing. It's obviously not there yet, and maybe it never can be, but if it is, that would be a huge value add to the world.
Think about it in other ways. Would you like to have a 4th season of Star Trek the original series, or more seasons of TNG or DS9 or Voyager or Enterprise? I sure would! Maybe it doesn't add any value to the world in your opinion, but part of the value I get out of the world is entertainment and enjoying great stories. It definitely adds value to me, and I'm technically in the world, so even if it's only a trivial amount in the grand scheme of things, it is still adding value.
On the subject of scientific advancement, there are surely mountains of discoveries just waiting for us in the data we've already collected, but as humans we're not capable of fully recognizing Long difficult patterns, especially when there are many variables involved. However, AI is getting very good at that. We Don't necessarily need AI to conduct original research and studies, but we can absolutely use it to comb through data and look for things we may have missed. The reasoning models are also getting pretty good and will surely get much better with time, and will be able to crunch through long chains of data looking for patterns. Working in tandem with a human scientist, there is potential even now. As AI gets more capable of being agentic, I think that will only increase.
The people who worship AI are in my opinion misguided at best, but that doesn't mean that AI is a nothing burger