By introducing its own stablecoin, it gives greater yield to XRP. And the more its stablecoin is used, the higher the value of XRP will rise. I think you read something wrong somewhere.

RLUSD (Ripple usd) is technically going to take XRP (Ripple) out of the game
It fulfills the same functions but with the huge advantage of being stable.
XRP for the moment is maintained by speculation and market FOMO