After reading this, I can account for some legitimate GPS uses. I've often asked the same question.
What I cannot account for is Canon asking me to pay for another non-photography gizmo that I do not want, do not need. As long as it's an offboard accessory, it does not affect me. Those few people with specialized needs can buy the accessory and use it all day long without affecting me.
But now they've asked me to subsidize their GPS needs, and that's not fair. And you'll have a hard time convincing me that enough people want/need GPS that it's a legitimate product enhancement in my photography tool.
This is one reason I am saying the 6D is not a camera designed for photographers. As Canon says in their product literature:
"...the EOS 6d is truly the Full-Frame DSLR camera for everyone."
I believe it's aimed squarely at the social media crowd who want everyone to see the lovely oatmeal they had for breakfast -- and see it right now! "Wow, they look like steel cut oats!"
This trend will no doubt continue, and I don't like it. I have accepted video, which allowed them to raise the price of my photographic tool because a lot of would be film makers are willing to pay for it. That and the legitimate needs of photojournalism, which is headed toward a video world and away from stills generally. But now I'm having to pay for GPS, WIFI, etc. What's next, a Facebook button, texting, having a phone call on my camera interrupt my composition?
Sorry, I'm sure this is more than you want to know. But I do have an excellent GPS unit. It has nothing to do with my camera, and I enjoy what it does for me. But I don't want to pay so others can have it in my camera! Let them buy the accessory and subsidize Canon that way.