I somewhat agree, but would like to counter by saying that the micro:bit has been an invaluable tool for me personally to teach fundamental hardware programming

I somewhat agree, but would like to counter by saying that the micro:bit has been an invaluable tool for me personally to teach fundamental hardware programming. The pi zero, while a great tool for more advanced programming, still requires some boilerplate knowledge of electrical engineering that surpasses what one would want to teach someone who just wants to make some lights flash. The micro:bit has, built in: a 5×5 array of leds, an accelerometer, a digital compass, 2 push buttons, a set of piezo / touch io, and a low-power bluetooth radio — all of which have api libraries and documentation that a user doesn't need to write themselves. While there are a multitude of awesome things that can be done with the pi zero, there's still a non-trivial amount of setup required to program basic hardware features.