I see... I just foud out what you can not do with the 6D. I was just interested in this cam, but I think not anymore.
I wouldn't call it a deal breaker just something you have to be mindful of. It also something that can't be overcome with good technique or simply realizing the limitations of what you and cant do. Is it fool proof? No, but then again nothing really is.
Well by the nowdays tech a decent 3d tracking is something that I personally would expect in a ~2000 € body.