Lightning is slightly smaller. But USB-C is more universal and a good charging solution. Switching iPhones to this charging protocol will be a nice improvement. Right now in my house I have three charging protocols that are used frequently, USB-micro, USB-C, and Lightning. I also have wireless charging pads, including one used only for my Apple Watch. The more stuff I can switch to charging with USB-C, the less charging cords I have to have around the house. And that will be nice!