The only use case that comes to my mind is extracting live data from device strictly recording onto SDcard, but wifi enabled SDcards designed for that purpose are already on the market since 2010 (eyefi).
I think it is for devices that are meant to be run for years on battery. I try to find the power consumption but no luck. If it is for that, no sure how useful are they in the age IoT and great MCU for 2 usd.