As far as I can check, this is not completely true when the program only reads from FS, like getmyancestors. I see no client key in that, nor in the source code of the gedcomx module used by this Gramplet. And that suggests that we may never be able to write to the FS tree with it, like you can do with an approved client like Ancestral Quest or RootsMagic.
I looked at the source code, and both getcomx and getmyancestors log on to FamilySearch using a fake User-Agent, meaning that they pretend to be Chrome or Firefox. You can see that in the source code, if you want. And I see nothing that looks like an encrypted application key or signature that you would most likely need for write access. The source code has entries that pretend to write to FS, but I really doubt if they work, and my first tests on close ancestors clearly suggest that they donāt, and that is fine with me.
There is another reason for not supporting it though, and thatās the language used by and in the source code. Variable names and text strings are in Esperanto, and many log or debug texts are simply printed to the terminal output without using gettext for translation. And that will make maintenance quite difficult for core developers. And in that respect, itās much the same as the isotammi tools, which also have text strings in another language than English.