Because they look a lot alike. Such as if you reinforced the design a little bit will it work?
It might - but the center of gravity and the tripod might not be able to hold the weight of the jib, camera, counter-weights... and personally, I think it would be a pretty expensive mistake to watch my $2,000 camcorder fall and brake because the camera crane collapsed under the weight. A mic tripod is designed to handle about a pound of weight. A consumer camcorder, the jib and counterweights (and maybe a mic or whatever else you throw on there) can be between 5 pounds and 50 pounds. That's why companies like Kessler make what they make. And that's why the companies that makes lesser camera cranes (Cobra, CameraCranes, and others) never use a mic tripod. They use a heavy duty camera tripod or other LARGE, STRONG, item - not a mic stand.