Fingerprint sensor, UMTS Modem, HiDPI Screens, especially mixed with regular screens, there were issues with low cpu power states or so on the recent carbon X1, my desktop sometimes locks up when the laptop is docked with external screens connected and only unlocks when I undock (it doesn’t crash, it seems to be incapable of placing a window, once I undock and redock everything is fine).
Sure, it runs: it boots and displays an image. It’s still much more work to make it work as smooth as an apple laptop.
Running Linux comes with some advantages and obviously the trade off work for me in the current circumstances, but it could also fall the other way.