If you look back to the history of the Apollo program, in-orbit rendezvous, vehicle assembly in space, and refuelling were all discussed, then discarded as too complex and risky. Instead, the Rocket was built big enough to do the whole job.

Now we're re-inventing the wheel and making it sound good.

How is a gas station in space better than ISS?

(Well, I admit it does then enable Lunar and Martian missions with our current crop of underpowered "heavy" lifters) But it also requires managing and station-keeping and regular rendezvous missions to gas it up.

It's basically ISS with an attached bowser.