[syzygyhack]

It may undermine why you want to use USDT. I don't see why it would affect your desire to use DAI, for example.

The point is that you can have it any way you like it. There are no hard and fast rules like "irrevocability" as described above.

You can have a contract be not updateable, final, and verify its source code to know there are no malicious functions. Or you can have one that is updateable by its developer. Or one that is updateable by an elected authority. Or updateable by a DAO of the contract's users. There's no single way to do it or perfect solution.

Like most software development, it is the understanding of application requirements and selection of tradeoffs.