They prolly knew with the computer effects, and all the other promotion and other crap, the real PV would take a while. So they probably didn't want to spend forever and a day filming a dance shot PV. So they knocked it out quick, crappy editing and all, knowing us fans would still love it and watch it 1.5 million times.
It just goes to show that angles are pretty much everything. Like even if her face was turned a little more like Reina's she probably wouldn't roundfaced.