Commercial spaces and some houses in the UK already have 12V DC lighting and sockets for spotlights using the GU5.3 socket. It lets you have smaller and cheaper light-bulbs.

They're not great to have as a renter, though; many of the AC/DC converters were designed for Halogen light-bulbs, and have a minimum wattage requirement, so the more power-efficient LED light-bulbs don't work. Plus, since the fittings are less common than E27, the choice of light-bulbs is much lower.

If solar power and home electric storage batteries become more common, we might start having DC run directly into houses, to avoid the DC/AC conversion from the battery, then AC/DC back to computers/light-bulbs/TVs. But that seems years away!

P.S. smart light-bulbs need to have individual micro-controllers if you want to have colour control. I rarely use the funky colours like green/blue, but I do love being able to go from white light in the morning, to a warmer/orangish light at night.