The persianate dressing has one function - to provide the Muslims of South Asia with a "high culture"
So they feel connected to Islam's glory days b/w 9th-12th cen, as opposed to feeling like disconnected local converts
But the dressing is "phoren".
Exactly as the Muslims of S Asia are also Indian for the most part in their genetic make-up and even habits, but with a foreign religious ideology
The Muslim population is huge in South Asia - about 500MM people.
They seek a stamp. A connection to the head-quarters of Muslim high culture. The glory days of Baghdad, Samarkhand, Isfahan.
But they don't want to just regard themselves and be regarded by Hindus as local converts
They seek a high culture. And because they have reneged on their ancestral faith, they cannot claim the Sanskritic high culture as their own
You have a third of this subcontinent who are Indian in their constitution, but their high culture has its roots somewhere between Damascus and Qandahar
That's the culture that has lent them their distinctive identity