I can see it going mainstream for stores and businesses long before homes. For homes, "tradition" is where it is at. For one, stores and businesses have room and space to run new wiring.
However, for something like a new build home? It would be dead easy, I think. 380V DC? You can push a lot of power over that with relatively thin wiring. LEDs are already long lasting enough(theoretically) to make "Replace the fixture" the solution when one fails over "just" replacing the bulb. Of course, you can still make things modular if you want, so you can do things like swap out a daylight LED for a warm LED if you darn well want to, or vice versa.
Consider a home that is being built with solar panels and a battery system from the start. The batteries put out something in the range mentioned - 380V. Maybe the solar panels add up to 400V, and the battery puts out something around 360V. This way you don't need any power converters at all. Much like the lights in a car - many can take anything from about 16V down to like 10. Car power is "noisy" by default.
As long as the DC devices are designed to operate within the expected range, the only difference is that the lights would be very slightly dimmer when on battery. Not necessarily a bad thing if they're only dimmer when they aren't fighting the sun's light and human eyes can adjust a bit.
Anyways, given LED efficiency you could light up most homes with a single 15 amp circuit run using 14 gauge wire. 15A@380VDC = 5k watts, at 50 watts per room that's 114 rooms you could cover. And I'm being miserly.
You'd have 2 breaker panels - one DC, which includes the lighting, and one AC, for traditional appliances. If it becomes common, I'd imagine that you'd start seeing more DC appliances. For example, there's no reason why you can't make a fridge that expects ~380VDC if you want, and as they mention, it'd probably actually be a touch more efficient. Electric motors tend to be more efficient at higher voltages anyways, and the first thing most induction motor controllers do is rectify the incoming AC to DC anyways, so as they say, eliminating the steps from the battery to the motor of DC -> AC -> DC -> AC(frequency controlled) down to DC -> AC saves you some power. For something like an oven or electric range*, well, heating elements don't care whether it's AC or DC. They just need to have the proper resistance for the wattage wanted. You could even get rid of the huge capacitors in things like microwaves and air conditioners.
*I remember when the idea of using battery power for this was insane, but it really isn't anymore.