Less energy expended in micro-G

Canadarm, for example, doesn't work on earth. They couldn't even test it. The expectation that it would work in space was based entirely on theory.

In micro-G, the Canadarm moved.

But you couldn't budge it on earth,

The zero-G environment allows a huge savings in energy.

That's just one factor - an option available to space engineers and very much worth exploring and applying to space construction and manufacturing.