Also is the usdt on bittrex the same as on bitfinex or there is something im missing here?
Nope. You can literally store USD/EUR on 70-80%% of the fiat exchanges out there. They don't mind that but you will not be able to withdraw or deposit any, you are only able to trade it to other cryptos or get it from trading other cryptos.
e.g., kraken, bitfinex, are the two major exchanges that do this.
Of course though if you stored money on bitfinex it'll pretty much be the same as storing USDT, since Bitfinex is operating USDT in the first place.
There are also other "pegged" cryptos such as nubits, or bitusd. But their values tend to fluctuate wildly.