The problem is easy to solve: your MacBook has a USB-C port, but the Apple Watch charging cable does not. Satechi has a simple solution. Their USB-C Apple Watch charging cradle is exactly like its sound, plug directly into any USB-C port to add an Apple-certified magnetic watch charger. It has a dark gray aluminum surface coating, which can be matched with many Apple products, and the body is very compact, easy to put in a bag or even a pocket. Click here for more details about this USB-C Apple Watch charging dock.
Satechi USB-C Magnetic Charging Dock for Apple Watch