It's the difference between "some human labor involved" and "zero". Getting to zero is very hard, and has very different ramifications then the "some" quantity.

As long as "some" labor is needed, then that's going to be the entire economy - it'll simply expand along whatever constraint that "some" represents.

The bizarre thing lately is all these arguments people make implying the economy is maximized. That all the things that will ever be needed are currently being produced and no new growth is possible or will ever happen (despite this literally never being the case in the entire history of the human race).