For me, I have no interest in WiFi for streaming images off to the internet. Most of my photography is done outdoors and very little of it is done in Wifi range of anything... probably a quarter of it is done outside cell phone range....
What I was interested in, was the ability to remote control the camera. That will be missed... and no WiFi SD card is going to give me those abilities.
My situation exactly, it's a pity that Canon don't get with the programme, WiFi isn't some new & unknown tech, it's been around for a long while now, Canon seems generally to have gone down the path of least resistance, add on at a reasonably large cost, pity.
I've tried a few work arounds, the only one that I absolutely recommend is the CamRanger, this system via my iPad Mini simply doesn't leave the bag, since buying the CamRanger I've just adapted it to pull those Images that are exceptionally hard to get any other way, great system, works great on the Canon 1Dx & 5DMK III also the 1DMK IV & 5DMK II, as far as I know works on just about anything.http://camranger.com
The attached Image I'de tried on a number of occasions using different systems, monopod down low etc, but the vehicle scares the Wildlife so the shots are difficult.
With the attached Image I set the 1Dx + 300f/2.8 II on the RRS small Metal Tripod to get the Camera down Low, attached to the CamRanger, in the middle of the Track, drove off 100 meters behind some bush, monitored via my iPad Mini in the vehicle, adjusted Focus via the iPad Mini, shot the Image via the iPad mini/CamRanger as the Mum & Cubs approached the "strange looking" object in the middle of the path.
The Image isn't anything wonderful, but I just like it as all the Animals have that look of being intrigued, although Mum did have a constant frown & look of suspicion. Difficult to get this sort of Image from a Vehicle, not impossible, but the CamRanger opens up new avenues for Imaging that had been almost impossible before.
Only real issue I've found with this method is shooting Lions, they tend to eat the Camera, not good.