I'm curious, do people regularly shoot at these ISOs, or is it simply used for easy comparative reasons?
I've just looked at my catalogue and 0.6% of my images were shot higher than ISO 3200 (highest ever was ISO 8000).
(It may be my old school methods as I prefer to use some sort of camera support, often improvised, and slower shutter speeds in such low lighting conditions. FWIW I don't shoot weddings or regular sports, but a wide variety of commercial and editorial subjects.)
I certainly wouldn't base my buying decisions on such extreme usage scenarios.
I'm not criticising anyone, just curious.