With the successful finesse in ♣, Declarer can affort to take the ♠ finesse, because his ♥ stopper is still in place. This play will guarantee a total of 11 tricks.

If instead Dummy's 9♣ winner is cashed now, Declarer is forced to discard the 2♥, unguarding his J♥. This could result in losing 3 tricks in total.