Yes, Macs have had USB ports for years, but Macs have been powered by proprietary charging cords up to this point. This new Mac is the first one that I can think of in the last decade that is using a standard charging cord.
So, what is next for USB-C? Considering Apple had heavy engineering participation in developing the USB-C standard, I imagine they will be using it in everything. Additionally, the European Parliament handed down their ruling on the issue of mobile chargiing standards and they say that manufacturers, including Apple, will have to use a standard charger by 2017. This timeframe lines up quite nicely for to move to a completely new design with the iPhone 8, complete with a standard USB-C charging cable, in mid-2016.
P.S. is already selling 3 cable accessories for the new MacBook (and they have the premium pricetag already included).