I’m still wrapping my bed around the concept of Tethers, but I don’t see [1] as problematic. That’s the same way that ETFs work — they ensure value parity by guaranteeing that you can redeem blocks of them for the corresponding assets. But to ensure the ETF shares aren’t all redeemed this way, they limit it to large blocks of shares. That way, smaller investors can still sell their (smaller blocks of) ETF shares for dollars at par, since any divergence would be an arbitrage opportunity that a bigger trader can exploit.

The requirement to redeem in large blocks doesn’t change that logic, and still ensures that the smaller trades happen at par.