If it worked flawlessly it would be amazing and much faster than SD. Adding SD could mean needing more space, a different board..etc. Who knows. If the Wifi was well done, this would be gamechanging, honestly.
The problem is that wifi either doesn't work, or when it does, it doesn't network with the laptop. If both of those things work for people, I doubt they are lamenting lack of SD technology. Especially since this is supposed to be a 5+ year device and SD is a bit long in the tooth.