From my perspective, the two main advantages with stereo mics are a quick setup, and the fact that most stereo mics are more compact and have a lower visual profile compared to separate mics in coincident position. That can be important for live performances where you might want Blumlein or M/S pair, but it can't be too visually obtrusive for the audience.
My one good stereo mic is a (discontinued) AKG C426b,and it's very compact considering the diaphragm size. The single stereo cable also helps with unobtrusive rigging, although it's a major PITA if anything goes wrong with the specialized cable.
One other consideration for large diaphragm mics like this, or ribbon mics, is that with a stereo mic you're getting a matched pair of capsules from the factory. It's relatively easy to find matched separate stereo pairs in small condensers, but for large diaphraghm mics and ribbon mics it can mean a special order from the factory, or matched pairs might not be available at all.