Case 1: “A person may surpass their peers, just as musk is remarkable despite its origin” — the issue is possibility: bayān al-imkān.
Case 2: “Among other leaders he is like the sun” — when the relation of ranks is being shown: bayān al-ḥāl.
Case 3: “Its blackness is like a raven's feather” — when specifying color intensity: bayān miqdār al-ḥāl.
Case 4: “Estranged affection is like broken glass” — when giving a warning enduring force: taqrīr al-ḥāl.
Correct analysis identifies the speaker's purpose, not just a familiar image.