Well 1 BUSD = 1 BUSD and people don't understand that 16 billion BUSD can become easily = 1 cent. Some might need a cold shower in order to improve their math. Sorry, I was wrong, Terra has provided that math lesson, but people have still missed the point.
But, but, 1 LUNA =1 LUNA if you don't sell, right?
And no, some will never learn, and some don't want to as they don't even care about crypto, for them those stable coins are the bridge to trade, as you mentioned for arbitrage and at the same time give them a false sense of security as they can withdraw those to their wallet and think it's not like a bank when in reality is worse.
I don't think USDC will get targeted by SEC because it was Circle who is file a report about the BUSD's reserved funds [1] so Circle have prepared anything in order to not got a same result like BUSD.
Or, a far simple version, they ratted out Binance so they will get a moment or two of peace and maybe enough time to come up with a solution.
And speaking of a solution, as mentioned above, they could go another way, they could issue stable coins in Qatari riyal, UAE dirham or Omani rial, since all of them are actually pegged to the USD, it doesn't change anything from a user point of view.