Translations are beautiful lies
Every English translation of Ghalib adds a paragraph of explanation for what one couplet does in two lines. The economy, the elegance, the shock of the original: gone.
You can't hear the music
Urdu poetry is built on metre (bahr), rhyme (qafia), and refrain (radif). These aren't decoration. They're the architecture. In English, you get the furniture without the building.
Wordplay is untranslatable
When Ghalib uses a word that means both "wound" and "flower," the entire couplet operates on two levels simultaneously. No translation can do that. You need the language.
You're outside one of the great traditions
Urdu poetry is one of the richest literary traditions in the world. 500 years of ghazals, nazms, qasidas, marsiyas. You know the names. It's time to know the words.