I don't know.

It's got some extremely simple rules. 1 data structure. And nothing is particularly hidden.

Python might be better for actually producing something, but from a 'teaching how computers work' pov, forth would seem to have it's merits. Python hides a lot of stuff, thus we have a situation where people think compilers and interpreters are magical things. If you don't care how the computer works, that's fine, but personally I'd like to teach my kid how a computer works, not how to use some programming language.