A machine that can do anything an average human can do whilst sitting at a computer.
Why replicate AGI? Wealth creation determines living standards and AGI would vastly increase wealth creation. That’s one reason.
What you want from AI is a different conversation. I agree the ultimate point of AI research is not necessarily to make AGI as per the above definition. It might be to say understand the universe or greatly accelerate technological progress. That’s a subjective call. But orthogonal to the problem of choosing a good definition of AGI.