As I said, stable coin can give profits if the fiat coin used to buy the stable coin losts value
For example, I live in Brazil and we use BRL, and I need 5 BRL to buy 1 USDT for example, and if I buy 100 USDT and one month later I need 6 BRL to buy 1 USDT it's a profit situation
So it's wrong to say we can't have any profit with stable, but it's not recommend, there are easier and better solutions to buy USD for example
understanding stable coins which I believe is if the coin falls one day but can quickly come back again. so if we can analyze it well and act quickly then it is certain that a stable coin will provide a profit value as well. but if it's altcoin obviously the profit value isn't much different if you hold bitcoin. bitcoin is currently stable, can go down with a decent value but in a few hours can go back again to the previous value, if you can anticipate it can definitely get a big profit.