The new MacBook Pro models as well as the 12″ MacBook come with USB-C power supplies. The advantage is, that a broken cable can be replaced easily. The disadvantage, that Apple does not include an extension cord anymore. You can use the one from your old MacBook though!
Apple wants to save a few bucks and doesn’t include an extension cord anymore. This is a bit cheap, sure, but there is an easy way around it!
If you ever had an older MacBook or even iBook in you life, you can just use the extension cord from an old power supply. Apple never changed the design of the charger, so the cables are all the same. So can use an older or broken power supply as extension cord donor.
Another advantage: you can connect cables for other countries, when you are on vacation. You can buy two pin cables everywhere and for every country for cheap. Just plug them in and you are done. Don’t worry about different voltages and frequencies: Apple’s power supplies can handle 50 and 60 Hz as well as 110 and 240 volts.