Well, if the GnuCash developers decide to do so, and I doubt they will, they won't take my route. I had to modify a system file, iso_4217.xml, after all. Furthermore, it works by pretending that the target non-ISO4217 currencies do qualify as ISO4217. That just strikes me as an undignified kludge.

I doubt that the developers will update GnuCash to include the bitcoin or any non-ISO4217 currency because they've stated that they won't include currencies that ISO4217 doesn't recognize. They also seem content with forcing users to make do, rather than coding a proper feature that would users to easily define their own non-standard currencies. Someone needs to actually code the feature and submit it. If the developers reject it then we can just fork the project.