Here you can see that same sort of squatting position that the male miqo'te /sit has with the forelegs held together and towards the ground, not resting on the knees, this way the center of gravity is more balanced and controlled. Obviously the anatomy of cats and humanoids is very different, but the male miqo'te /sit is about a close as a humanoid can get to this position. We'll call it the "cat sit" for ease of use. 

Why model the /sit this way? Well, primarily it's because of the readiness advantage it gives you. Sit yankii zuwari, with your feet flat out on the ground, and try to get up quickly. You can launch yourself up easily enough, but it's a little difficult to control the direction of your launch. 

Now try the cat sit, with your arms forward while balancing on the balls of your feet. From this position it is extremely easy to launch yourself forward in any direction that you please, one might even say it's easy to pounce from this position (see what I did there? lulz). Furthermore many sprinting mammals run on the balls of their feet because it takes advantage of all that energy supplied by those leg muscles. In summation I think the male miqo'te sit is more about sticking with the whole "cat boy" theme than it having anything to do with yankii-zuwari.