A particular utterance may display an elegant rhetorical ornament. Its presence shows a feature of that utterance, not necessarily a settled ability to produce baligh discourse across many occasions.
Keep two questions apart:
1. Quality of this utterance: Does it contain an apt literary device?
2. Capacity of the speaker: Can the person reliably compose fasih and contextually appropriate speech in varied settings?
The next chapter, balagha of the speaker, defines that stable capacity directly.