Lots of people use SD cards as basically "permanent" extendable storage. And this is something that's much more necessary on lesser Macbooks because they come with such limited standard storage. A 256GB SD card is under $40, while adding that much storage to the SSD in the Macbook is hundreds.

HDMI is just one of the many display ports around, and the people using it are probably tied to a desk or something, so having a dongle for it is really no big deal.

I don't mind using my Anker for HDMI, but it sucks that I have to use it for SD.