[dragonwriter]

> That's interesting, my Cryptopia DOGE trading pairs (and LTC) beg to differ.

How?

> USDT is one of many trading pairs offered by crypto exchanges.

USDT is not a trading pair, it's a single cryptocurrency. The issues that give it a special role, both tied to it's USD peg, is that:

(1) It is sometimes treated as equivalent to, and commingled with, USD by exchanges (notably, Bitfinex), and

(2) USDT:<X> trading pairs, on exchanges that don't handle USD lat all, are often treated by the community as if they were USD:<X> trading pairs.

(3) The special role USD has in world markets.