Atmosphere can still be handy! You can use it for aerocapture or aerobraking or aerocapture, massively reducing delta-v for trips to that body. Same with gravi

Atmosphere can still be handy! You can use it for aerocapture or aerobraking or aerocapture, massively reducing delta-v for trips to that body. Same with gravity - useful for gravitational slingshot maneuvers or high trust burns making use of the Oberth effect. You might even land once on the planet, so that your von-neumans can shoot it into space in chunks for further processing.