May be its not a smart question to ask but I need to know how to people profit from buying sablecoins?
The way to make profit from stablecoins is to change from BTC to your chosen stablecoin when the BTC price is high, and then change back from stablecoin to BTC when the BTC price has fallen, thereby increasing your BTC holdings (although your holdings in terms of fiat won't have changed, until BTC price rises again).
Either that or figure out some way to short Tether in the next few months before it completely collapses.