Hi,
I don't really know a lot about Tai Chi etc., but here in NZ it is funded by our national accident insurance provider for the elderly population after falls.
See here:
Practice Tai Chi

They also list some evidences, such as this one:
Wong, A., et al, ‘Coordination Exercise and Postural Stability in Elderly People: Effect of Tai Chi Chuan’, Archives of Physical Medicine and Rehabilitation, 82, (2001), 608-12.

I couldn't find any evidence (quick check) for Tai Chi to improve physical movement (maybe you need to be a bit more specific), but it is certainly used in falls prevention.

Hope, this helps,
regards,
Fyzzio