The thing is, if you want to poke at a device interactively, your options are either Forth or (if the system is beefy enough) one of these scripting language ports; tethered C interpreters are not precisely commonplace. And while I love Forth to bits, most people will probably go the scripting-language route.

A whole 8 bit computing generation was able to jump into computing thanks to scripting.

There are some differences, but broadly correct (eg., the program is precompiled and the experience is definitely the best in VSCode; plus of course different language).

However, I heard of uPython being used in production deployments, though maybe not in millions of units.

(I'm working on DeviceScript)