The way I see it, if its creator made software with it, then it's a bona fide tool for programming. The fact it hasn't yet spread to more developers than those involved in the project doesn't negate its "fide"s or "tool"-ness.
If you made a parser for a scripting language for content for your application, or a DSL for your colleagues to use, would you claim they weren't "bona fide"?
It's a somewhat better art project than Brainf*ck or Piet because linguistic barriers are more culturally significant than "just because I can" exhibitionism, but it has the same practical usefulness. Arbitrary obstacles make sense in conceptual art, not in tools.
If you made a parser for a scripting language for content for your application, or a DSL for your colleagues to use, would you claim they weren't "bona fide"?