Right now LLMs only have text, images, and videos to train from. Anything it understands about physics is from an abstract level. It's like learning how to calculate throwing a baseball before you've ever even thrown a baseball. Imagine having to learn force = mass x acceleration before you've even picked up a ball.
What this world generation Google is doing appears to be something Nvidia has spoken about too. Letting LLMs/AI learn from a world physics simulation. Meaning LLMs having the opportunity to "experience" physics, the same way you intuitively know how to throw a ball after attempting a few times yourself.
If an LLM can better understand how our real world works the quality of its output improves -- theoretically.
As far as your taxes go, you can create an intelligent workflow right now to do that for you. Don't need AGI for that.