Dirt Cheap 4K 60fps Cameras on Amazon: What's the Catch?

I've been looking into getting a new camera specifically for Video and I noticed there are tons of 4K 60fps video cameras being sold for as little as $100. Common Sense tells me they're bad cameras but I can't help but wonder: why are these cameras so cheap, and what's the catch?

If anyone knows about or have used these camera's before I'd love to hear your thoughts. Even with subpar build quality and a lack of features, $100 is laughably cheap. maybe there are even more serious concerns like plain false advertising?