https://www.cnet.com/news/new-sd-card-uc-express-specs-tout-128tb-max-up-to-almost-1gb-per-sec/

The new "UC" spec extends the maximum capacity of either a full-size or micro SD card from 2TB to 128TB. And the "Express" spec increases the peak transfer speed of a full-size card from 624MB per second to 985MB per second. 

That, in theory, puts SD in a better position to use high-bandwidth file types such as 4K and 8K video, as well as for expansion in small devices.