This is actually hilarious. They remove every single port and replaces it with a single port no one has a single accessory for. And as a final F*** you all B***es the port won't work with the dongles that you need to make your stuff work.
That new 'spaceship' of theirs is actually a Death Star.
Actually it's not that bad. People has been using USB-C accessories with Thunderbolt 3 ports, and that is cheaper than Thunderbolt solution.
http://crazydiamondstar.blogspot.com/2016/08/usb-c-dock-best-baymax-for-macbook.html
USB-C Dock from Caldigit, OWC or Plugable should work with the new Mac's Thunderbolt 3 ports.
Caldigit's one is working well and has been confirmed by several users, not sure about OWC's and Plugable's. But definitely Plugable's Thunderbolt 3 dock does not work at all. That's been confirmed by this thread.
I would stay with a company that is more "mac-centric" such as OWC and CalDigit. Safe and Sound.