While the 12-inch MacBook is full of Apple's latest technology, such as the Force Touch trackpad and a freshly designed keyboard, it is also more advanced in its minimalism. The slimmest and lightest MacBook yet, the new model is built for a wireless world, and includes just a single port. While Apple has a history of simplifying its devices by gradually removing components like optical drives, Ethernet and FireWire, trimming down to just one port is more than just an abandoning of certain technologies, it marks a march away from wired life altogether.
The lone reversible USB-C port is versatile, and will handle charging, data transfer and video output just as previous combination of ports have been able to. However, to do so requires a compatible cable, and as this has not been the standard for very long, they aren't exactly easy to come by. Plus, new MacBook owners will find the current cables they use to connect to remote monitors, photo card readers, external hard drives, etc. useless without a dedicated adapter dongle. Apple does sell three-pronged dongles that can turn the single USB-C port into a power adapter, USB 2.0, and HDMI out, but they cost $79 each, a costly necessity just to continue using your existing components.
Apple has a solution: you don't really need all of those cables. As frustrating as it might be for now to have a solution that takes you back to the source of the problem, Apple could prove to be right in time. It has sacrificed functionality in the present for a leadership role in the future before (the original iPhone did not support already-popular 3G service at launch, MacBook Air does not include disc drive, etc.), and it has paid off, in part due to its pushing of the issue. Until it does this time, however, you might want to hold onto your cable compatible devices.