Agreed, and I assume the main use case is for websites to be able to offer a "dark UI" like maps apps do, so if you're using it for navigation at night it won't

Agreed, and I assume the main use case is for websites to be able to offer a "dark UI" like maps apps do, so if you're using it for navigation at night it won't blind you. But here's a crazy idea for them: @media (prefers-color-scheme: dark) { color: white; background-color: black; } That way it doesn't leak any uncontrollable information, and it makes the UI look how I want it to! It can even happen automatically at night if I've set my phone to do that. Downside, if I drive through a tunnel during the day the UI stays bright. I'll live. If they really think they need to access my light sensor, they can ask. Maybe someone wants to make a light meter web app, I don't know. But I do know they have no business accessing sensor hardware without permission. It's like with the battery API, people had this idea that web developers could say "Oh your battery is low, we'll throttle back into low power mode to respect that." But instead, websites are happy to continue burning all the CPU, data, and battery life in the world, because by and large developers aren't paid to give a shit about your battery. They're paid to ship features and make whatever metrics go up. So the only thing it gets used for is identifying phones for advertiser targeting.