[__natty__]

Why not for 3 eur buy some basic arduino or other tiny hardware to tinker with and for another few eur, tiny i2c/oled display, wires and set of basic switches? You start programming with option to expand to the larger project in the future. You have constraints of real device, community is much larger and there are more learning resources.

[layer8]

Because those don’t boot into a fixed interactive programming environment with a BASIC-like language and REPL to easily do simple things on the same screen and using the same keyboard you also use for programming. Your proposed setup has more complexity and is less intuitive for a learner.

[Tepix]

For starters, there is way more friction both in buying hardware and waiting for it to arrive and developing on real hardware in general.

I agree however that it's super cool to have real hardware to run this on.

[newswasboring]

Because moving a sprite is much more exhilarating than blinking an LED.

[yard2010]

Well how about moving a sprite by blinking a few leds?

[jrmg]

Because those require you to get to grips with “a tiny i2c/oled display, wires and set of basic switches” when you’re interested in coding, not hardware.