USDT is extremely stable and is a stable coin class of crypto. Pretty much always $1 or like $1.01 so yes any bitmart sales go to USDT. I have a bunch in my Bitmart account and am waiting for the prices I like to buy more of some. Bitmart also has a bid and ask price so you don't have to buy at market if you don't want to. You can set an ask price to buy and a bid price to sell. just like Etrade or Ameritrade for stocks.
Market Data 
Markets 
AI
