Not necessarily true, there are a handful of users, who bought it for specifically for its video capabilities (YT seems to be a big thing these days and this is still one of the best cameras out there for that specific purpose), but of course with the intention of taking stills with it as well, so it is a hybrid camera in that regard. Compared to the other 4k60p capable camera, the GH5 it has video AF and it is also a much stronger stills camera and of course it fully belongs to the EF lens system as well (no need to use adapters, etc.).
And no, you can't get a C200 for the same amount of money, it costs a good bit more (and actually the 1080p120fps is actually weaker than the 1DXII) and of course it is video only.
In theory, Canon could make a smaller camera to give access to these features. But they simply don't, so if someone is looking into getting a Canon for video, he has to go for the 1DXII (or higher) to get them, simple as that. Apart from C-Log it is still a massive upgrade over the 1DC (which is basically only usable for 4k24p and it has a s35mm crop mode 1080p, but it doesn't even have a decent 60p slow-motion mode, or AF, and the rolling shutter is much worse) as well as being a lot more accessible pricing-wise.