Yes, it will be used. Dance and gait analysis are modes that come into play after people have used up and hacked through the easier things like eyeballs, faces, and fingerprints. They're also used as rather brutal filters in searching for people "healthy enough" to qualify for things like insurance or gym membership.
Allow me to point out a couple of obvious drawbacks to all the motion-based modes: they're much less reliable for people with certain physical conditions, especially variable ones, that mean they might move differently from one day to the next. Acquired disabilities will also fuck it up. Now multiply that by the number of people to whom those traits apply, and you can see why it's suboptimal. But it will get used anyway, because once you've trashed the previously mentioned options, your choices are to use shoddier options or give up biometrics, and very few civilizations will give up biometrics quickly. They usually want to ride it into the ground and make life really miserable for a long time.