Great for users, overdue
Many dark mode users welcome Safari automatically darkening sites, especially ones like HN that never added a theme, and note sites can opt out with color-scheme: light only.
Dark mode hurts some eyes
A large group with astigmatism, migraines or afterimages says dark pages are unreadable and wants the reverse: a way to force dark sites into light mode.
Developer and standards worries
Some fear broken layouts and design loss, criticise the binary light-dark() naming and the WCAG 4.5:1 target, while others argue the browser is the user's agent and sites should just support prefers-color-scheme.