Ok but imagine the Enterprise goes to help people on this planet where everyone lives underground in the dark because of radiation or something. Like it's bad enough that hundreds of generations have lived underground and, over the course of time, have adapted to the darkness so well that light sources actually hurt them. So Picard has to figure out how to help them without sending people in with lights.
And the obvious answer is to send Geordi down, but the settlements are so far down the communicators cut out and Picard isn't sending anyone into that alone.
"Data and I should be able to handle it," Geordi says. "Neither of us need light to see and Engineering can manage fine without us for a few hours."
Picard nods and is on the verge of sanctioning the mission with his trademark, "Make it so," when Data speaks up.
"Actually, my visual sensors are designed to be as much like the human eye as possible," he says. "They only process information transmitted by the reflection of light off physical surfaces. My ability to function onboard Enterprise in unlit spaces is due to my memorization of both the ship's schematics and the design preferences of those whose quarters I visit regularly."
Behind his visor, unbeknownst to the rest of the crew, Geordi blinks as he tries to process this new information. He's almost about to apologize to Picard and Data for the assumption when Data continues.
"However, I would be able to integrate the information from our tricorder scans to navigate without much difficulty. I could accompany Geordi to the settlement and provide some level of assistance."
Picard looks a bit confused at the correction, but nods. "Make it so."
Later, when they've beamed down into the caverns, Geordi asks why Data never mentioned that he couldn't actually see in the dark. He would've turned the lights on if he'd known.
"I did not need it," Data answers simply, as if that was explanation enough.
"Data, most people like the lights to be on, even if they don't need it," Geordi points out. "It's a comfort thing. And polite, too, I guess."
Data pauses, processing. "I was not uncomfortable, nor did I find the lack of light to be rude. I enjoy our conversations in the dark."
"Huh." Geordi stops, watching as Data continues down the tunnel a bit further. "But you keep your quarters dark sometimes, too."
"Spot is nocturnal," Data explains. "I have read that it is important for cats to maintain a sense of routine, including a regular day and night cycle."
"You do your work in the dark for Spot?"
