Sort:  

Is USDT considered a normal altcoin?

USDT is an alt coin that is virtually "tethered" to USD fiat, with very small price fluctuations. Currently USDT is valued at $1.02, so technically its more valuable than USD. I use USDT as a way to leave the market without converting back to fiat. https://tether.to

Yeh it will be fine with any crypto with enough volume paired against BTC

Yup, it will work the same, there are many traders who only use BTC as their base currency to pair.