I think it's the interior decorator philosophy of how lighting a residential room works.
For example, a single, central ceiling light is "the big light" , but having multiple lamps and/or wall lights that use warmer, diffuse light are not "the big light".
It's generally seen as cheap, lazy, and bad vibes to use "the big light". Boomer or unaware millennial behavior.
Imagine entering a chill, groovy, warmly lit room, decorated by hippies and feels cozy or not hostile, and comfortable and welcoming and relaxing. That's the opposite of "the big light".
Or I could just be fucking wrong and thinking of something totally different /shrug