Same reason some Losi's will bind with some Spectrums - they are made by the same company under license for the other and are re-badged.
Futaba has started making sure that their re-badged stuff will not work with their higher cost radios, I guess to eliminate a cheap option.
I might not have it exactly right in Nomadio's case but thats usually why - either licensed the tech to use or using re-badged product. Totally unfamilar with Nomadio.