The Hebrew that is translated as “worthless idols” or similar in English is translated in Kutu as vinyago or “idols,” “because all ‘vinyago‘ are worthless and by putting the adjective on it then it might give the people the idea that there are idols that are ‘useful/good.'” (Source: Pioneer Bible Translators, project-specific translation notes in Paratext)
See also idol / idols and these worthless things.