Owner of a 6d and a 5d3 here. In regards to wifi ---when i got the 6d I thought the wifi was kind of neat. I used it here and there (via the remote app). It took taking selfies to a new level! that, and every once in a while, like on vacation or something I'd use the remote transfer app to upload something to facebook. LOL...other than that, I have barely used the wifi. It has stayed in the off mode for like 98% of the time I have had the body.
I used to think wifi on an SLR was a dumb gimmick, but I now wish I had it on my 5D3. Some of my editorial clients now want to art direct shoots in real time. Fortunately, this isn't for every shot, but just for the more important ones that may be used as cover images. Without wifi, my ghetto solution is taking a pic of my camera's LCD screen with my smartphone, then texting in to the client. Wifi would sure make this agonizing process less painful.
Being able to trigger the camera remotely and seeing the images on my phone would also save tons of time when I have to rig the tripod up someplace that's difficult to access (like the top of my van
I'll probably just have to suck it up and get a Cam Ranger.