But visuals are important to Starfleet nevertheless, otherwise they wouldn't bother to light up the starships and their pennants.
I'm sure the lights would be useful when somebody else besides the starship herself is at work. Say, they'd be an excellent aid for spacewalks and work pod operations, or for inspecting and handling objects in the ship's tractor beams before they are moved to or from the ship's holds. Apart from that, though, it would probably still be standard procedure to illuminate any starships or other objects encountered unless they are polite enough to illuminate themselves. Sensors may be fine for navigating, docking and so forth, but the heroes still want to see what they are up against.