It travels fine for house-like distances. It'd be a lot more efficient if we used a single high quality rectifier at the point where our house join the grid. Good Transformers and Rectifiers are quite expensive. We just experience crazy sums of lossage these days with all the lousy rectifiers we shove into the wall.
Yes which is way datacenters are looking at possibly running DC in house it ends up being like a 10% savings I believe.
The issue here is if the world switched to DC at the home... Look around your house. Now realize just how much it is going to cost to retrofit your home. Now look at all the products in your home and realize how many of those will need to power connections to take advantage of the DC system. Now realize that you would need to do this on a massive scale before companies started selling stuff was DC options right out the box.