A stable coin backed by 1 USD functions better on a blockchain, ya traders could convert it to directly to USD but what if then they want to move it to another exchange? It would have to go through a bank and then to the other exchange. This is why tether was so popular, it was a away for traders to keep away from the volatility but still have the benefit of the blockchain.
As Dimon said ultimately it will be US dollars moving around on a blockchain....not bitcoin, unfortunately he was somewhat right.

I like your opinion with regards to changing of exchange, I think that is really true that we cannot use send the usd to other exchange unless it is a Tether. I think this is one of the reasons we really tether so we can transfer our coins without losing its value.
The point i was referring to in my question was I was looking for when you use the same exchange, I want to have my coins to have a permanent value, as of the moment the only exchange that I see doing this is an exchange in the Philippines

as you see in this exchange, you can directly trade your BTC and other cryptocurrency to fiat. for it to became stable. just like what we are doing to TUSD.