I feel that seeing your partner's pleasure is a major part of sexual enjoyment, so it greatly boosts my pleasure if I can see her orgasm. It can also be physically painful for a woman to be highly aroused but stop short of orgasm, so sometimes it is really important to finish what you started

That said, I try not to be obsessive about it - if she feels she 'has' to have an orgasm to please me, it puts us both under performance pressure and that detracts from intimacy and closeness.
Much as I enjoy my partner's orgasm, I love her, not her climax. It is a great expression of joy and life, but it is the cherry on top of lovemaking, not the main course.
Sometimes one of us climaxes, sometimes both, sometimes neither - the important thing is that it is a fun and shared activity which brings us closer.