The standing ovation ending is most common in a certain kind of biographical film: One about a person whose great contributions to society were largely overlooked in their lifetime.
If an audience wants to give a movie a standing ovation on their own, that’s their prerogative.
The subjects for these movies are chosen specifically because they led unconventional lives; they did incredible things and changed the world.
It feels like a false upbeat note grafted onto a downer ending to keep audiences from getting too depressed.